Hi everybody,

Right now my car shudders VIOLENTLY and doesn't have all it's power when I briskly accelerate under 35 MPH. It seems to clear up north of there, unless I step on it. It shudders some but it gets up and goes. The CEL is constantly on.

Backstory:

The car has 135K miles. I did the plugs myself 20K + miles ago. The timing belt service was done around 105-110K miles.

The car started to lag a little three or four days ago. I had let my oil go a good while before changing. - 8K overdue. CEL came on. Uh oh. I changed the oil with Mobil 1, like always.

I also noticed that the hose from the air filter box to the engine was split. I replaced it and the filter while I was at it.

The CEL was still on and the car seemed no better. I Seafoamed it. The car REALLY improved. The CEL went from solid to flashing to completely off. All seemed great.

Next day the violent shuddering began. I pulled all six coils with the engine running. Each coil removal, the engine would shudder. So I guess all six coils and plugs are good. My idle seems smooth and the RPMs stay just above 600.

I added Lucas to the fuel tank. Thinking I bought bad gas, I filled up with more premium. No improvement. Hoping against hope, today I put in 100 octane Sunoco. No improvement.

I'm assuming that the EGR being stuck would only result in a rough idle, right? Not the acceleration issue?

Thoughts?

 

Does currently have a cel on? Have you read that code? 5at or 6mt?

 

Hi Josh,

Sorry. 5AT. The CEL is on hard. I need to take it somewhere to read the code; I don't know how / don't have the tool.

Looks like I can get one from Amazon... Any suggestions to brand / model?

 

^i would just get it read from an auto parts store. that will be the quickest way to finding out what your problems are. and its free at the autoparts store, like autozone

p.s. always start with the code, as it can tell you directly whats wrong.


if you're adamant on getting a code reader, i would get a cheapy 30-50 dollar one.
or, get a bluetooth OBDII dongle and buy the torque app for your phone or tablet

 

Cool. I'll head to Autozone now.

 

report back with code and description of code

 

The good thing is if it were low compression it would be worse at idle and better with throttle/rpm.

The EGR as you noted would cause a rough idle or a stall. It can effect higher rpm and load but if there was enough EGR getting through to do that, the engine wouldn't idle at all.

Being speed density, it's not affected by the tear in the intake pipe.

Is there any difference from cold to hot?

What is full throttle performance like, has it ever popped back (backfired from under the hood)?

Ignition problems usually get worse with heat and load, so most of the time idle might be ok and the more throttle you give it the worse it gets.

The CEL will point you in the right direction but since you Seafoamed it which I don't recommend you do, make sure it didn't screw up the MAP sensor and make sure any vacuum lines are on tight. A vacuum leak by itself won't cause it to run bad especially once you start giving it throttle.

Is it starting in first gear and shifting normal?

 

funny, cuz that's how my car is running.
at idle, it sounds like it has a cam. "lug lug lug lug" 1st gear take off is kind of rocky, but after that i can accelerate pretty briskly.
I'll finish taking off the heads this weekend. I wanna see which valves were damaged!!

 

Just got back. The codes he gave me were:

P0300 through P0306. Said there were 12 codes in all, but it was those repeated.

So misfires on all cylinders?

 

^disconnect your negative battery cable.
then reconnect the cable.
this will clear the codes and wipe the nav and radio. Be sure to have the nav and radio codes handy.

if the check engine light comes back on, you have a real problem.
but for now, we need to test to see if they come back.


and it could very well be the EGR valve being stuck open by carbon deposits.
The EGR is easily held on by two 10mm bolts. remove those and check the bottom of the EGR canister

 

I Hate Cars,

No difference whether cold or hot.

From a dead stop, if I floor it, the shaking works itself through before 40 MPH and then I feel the power return to normal. If I'm doing 35 + and then I floor it, the shaking is not as bad and lasts a sorter period. Both instances it seems to work itself out before shifting to a new gear.

 

justnspace,

I tried unsuccessfully to remove the EGR yesterday. I could not remove the nuts. Mine aren't 10mm. They're a little less than 12mm. I couldn't get them to budge and they started to strip.

I mention the size, because I might be doing it wrong / trying to unscrew the wrong thing.

 

Its not the EGR. The EGR would throw a code by itself.
Any code that is 03xx is misfire as you already found out. Def reset the ECU/battery trick first. If you the code comes back up read it again.



Odds are that the 12 codes are the 6 misfires, plus the 6 misfires (confirmed or pending depending on the code reader they used). Reset it first.
I hate Cars, I am quite familiar with this car, but I can not remember.. is there an ignition control module or driver? I can not see all 6 coils nor plugs being bad, but I could see something similar giving it a random misfire code. Ill do a little research now and see what I can come up with.

edit: no ignition control module... all controlled by the ECM.

 

I was kind of guessing.
did you try 11mm?

the EGR valve is the black cylinder with like a brown tapered hat looking thing.

 

Ok. I disconnected the battery. No CEL on start. Started to shudder when I accelerated. CEL flashed. Went off. This happened with each moderate acceleration. CEL did go off each time, unlike the last day or so when it has been on constantly.

Will go back to Autozone. Manager there is kinda jerky. Really don't want to deal with him again...

And on top of all this, I just noticed that my rearview mirror has developed the dreaded bubble of death.

 

justnspace,

11mm socket is too small. There's play in the 12mm and 1/2. the 15/32 might be best. My problem is I can't get the sockets seated all the way because the shape of the EGR makes it really tough with the socket extension.

Plus, I only have 10mm & 13mm wrenches - figures Back to the store I guess.

BTW - I really appreciate all the help you all have provided so quickly.

 

the things we do for our cars.


if the codes came back that quick, that means you do have something going on.


and we know about those JERK autozone managers, right Josh?!
kidding.

hope you get to the bottom of this.

I recently went through something similar, except I know what the problem is.
I have a six speed and a friend performed the money shift and broke things in the engine.
i skipped the leak down test and compression test because I already know that I lost compression.

if it's not the spark plugs or coils, that would be your next step....to get a leak down test and compression test done.

 

gotta ask these questions;
have you ever drove through a large puddle of water, sucking water in?
has the car ever been over heated?

 

Well, I do live in Florida and it has been raining. I can't remember driving through anything I haven't driven through before and never had an issue.

If it is water, will it just work its way through, or do I have to do something?

The car has never overheated.

 

EGR will affect idle the most.

A while back people were having lots of failed coils from water in the ECU whether from the windshield being replaced and not sealed right or from a mechanic plugging or just natural plugging of the AC drain. Still though, it wouldn't clear up from heavy throttle at higher speeds.

If all cylinders are misfiring I would look toward something that could make every cylinder misfire. The ECU, fuel pump (has it ever backfired though the intake, a pop from under the hood?), or worse, some wiring/ground issue. EGR would be suspicious but it idles ok.

Is there a clear cutoff speed where the misfires stop, by rpm or by road speed or by gear?

I would even go with a valve adjustment but idle would be affected the most.

What about vtec, does it clear up when it goes into vtec?

Has it ever had trans work? It's not the trans but I've seen wires smashed between the engine and trans plenty times and sometimes they take a long time to ground out.

It's not compression because it idles ok.

 

Damn right hahaha.

And the only other thing I can think of to check would be to check the spark plug tubes... see if they have water or oil in them.
What that would cause is a different path of least resistance. It would cause the arc from the coil to the plug to be re routed..

IT seems like it could be a likely scenario as it hops from cylinder to cylinder and only sometimes. I dont know if the car sees more or less voltage under certain loads which is why it only happens sometimes, but it theoretically could make sense hahahaa.
Im running out of ideas at this point.

//sumary. Check for fluid in the spark plug tubes and at the bottom of the coils.

 

Guess what? I just did something stupid. THe last run I did in the car, I had left the EGR unplugged by mistake. I didn't notice a difference. So does that mean the EGR wasn't working?

There was no CEL on when I started the car just now before noticing that it was unplugged.

Then like a dork I unplugged the connector right above and clipped to the intake hose. Stalled the car and no it seems to idle right under 1K.

 

Josh,

I'll let the car cool down and check the spark plugs / tubes. If there is moisture, how do I dry them out / fix it?

 

Some more brilliant mechanical advice brought to you by Justn and the power of google search

 

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I just pulled the plugs. Two were clean, two a little dirty and the other two have oil up the plug.

 

Are you sure you didn't do a 1-2-1 or 2-3-2 shift at high(er) rpms? Sounds like mechanical damage in the head (i.e. bent valves) to me. That oil on the plugs isn't a good sign. Bad rings, valve stems, etc...

I'd get a compression AND leakdown test done next.

 

pbook4g5,

It's a 5AT, so I couldn't have done some crazy shifting.

Could the oil on the plugs be from not having them in snuggly enough? If so, would that also account for the misfiring? Could Seafoam have caused plugs that weren't tight to loosen?

Should I try putting the existing plugs back in, or go for new plugs?

 

Ah, thought it was a 6spd, so thats ruled out.

Yes, it could be from the plugs not being tight. Did you hear a ticking noise before you removed them when the engine was running? Our motors like to pop plugs out... especially cylinder 5. The easy check is to screw them back in and drive and then pull them back out and examine.

Seafoam wouldn't cause the plugs to loosen. The worst part about the Seafoam (which is probably why some people don't recommend it) is that it loosens up garbage and sends it through your motor, increasing the possibility of it getting stuck or damaging something on its way downstream.

How do the electrodes look on those plugs? How many miles are on them? Also, when did you have the timing belt done? Some of these symptoms sound like the car is out of time... but that would have been noticeable immediately after the change I would think.

 

I did the plugs around 90K. The dealer did the timing at 105-110K. It just hit 135K.

I don't know if I'd know a bad electrode from a good one...

I need to go get a torque wrench. Didn't have one last time. Maybe that'll make a difference this time.

 

Was just told by another guy at Autozone that it could be a valve cover gasket that needs replacing. He said that would account for the oil on the plugs and the misfires. $40 with tax.

 

Install new plugs.

If the misfire still occures I would suspect faulty injectors (Most likely clogged). Seafoam takes a lot of crap from the top of the engine down to the cambers and in theory it's suppose to be burned off. I did a carbon cleaning with a machine that connects to the fuel system. The machine did a great job, it was when I did a top end cleaner which sent crap down the intake to the combustion camber and bent number 6 cylinder rod. Just enough to cause a slight tap, misfired only when it happened. I drove the car for another 2-3K before figuring it out after pulling off the head.

 

Does no else else see all the oil on plugs 2,4,and 5?
Def need spark plug tube seals at the least. Which usually come with the valve cover gasket.

Part number is VS50607R

 

and if the plugs werent tight, that would COULD account for the misfire.

If it were my car,
Valve Cover gasket and spark plugs for sure.
Reset the ecu and go again!

 

I'm not blind thank you.

However let's talk about this.

Basic's here. An engine in a very simple term is like a giant vacuum. It runs off the basis of fuel, air, spark bang boom combustion cycle to power. Air being pulled in, fuel being drawn in and magic happens there after. Now that we have an idea of how engines work let's go to the next step. Carbon and oil builds in within the intake manifold and runners. When using strong cleaners like sea foam or even tb cleaner spray you break down the carbon and start the cleaning process. This, in return looks a lot like dirty oil.

Remember that logic of how an engine works? Like a vacuum? Now what happens if excess carbon, oil and liquid gets into a high compression engine like the TL? Simple, It for sure will foul the plugs, which is why they will look oil soaked and if enough of this crap gets in there (Just how I experienced this 1st hand) it will in a sense "Lock" the cylinder. Only so much can be compressed in the cylinder. Could he have an issue with his valve cover gaskets and 0-rings leaking?.. Possibly, but ironically enough the TL has 2 heads. Likely hood of going through both valve cover gaskets and 0-rings failing at once, is not likely at all..

Why did the car misfire when he used Seafoam. Simple, either too much at one time will cause a misfire because of Plugs being fouled, injector heads being clogged or mechanical issue. Also doesn't help OP going 8,000 miles over the mileage for oil service. If it was enough oil starvation, he would have a friend come knocking.. Get it, rod or bearing knock. So, how the hell does the injectors get messed up it's not even direct injection, simple back to basic's what's an engine again? A giant vacuum.. So for whatever gets pulled and get blown back up in the manifold will certainly do a number to the microscopic size holes in those injectors to spray. Even on TL's that I warranted injectors that only had 30K they still caused an issue under hard acceleration misfire.

Now another thing. PCV is located on the front valve cover next to the dip stick. Just like anything else this is still an important maintenance item that is also always skipped on the TL. Certainly running over due on oil doesn't help it out either. If the oil started to sludge it will certainly be a huge headache. Another thing, have you ever removed the intake manifold off these cars? If you have, you like everyone else will notice oil sitting in the intake. When you use the engine itself to clean it out where do you think it goes?

In short,

Highly recommend using OEM new plugs.
Replacing the PCV valve
Using good premium 93 gasoline

If it doesn't resolve the issue of a misfire

-Inspect and test the injectors / Replace faulty injector(s)
-Scan for codes

Lastly, IF his valve covers do need new gaskets and 0-rings. While he has them off, to inspect for oil sludge and inspect the cam for any wear in case there is sludge

I'm a certified technician for over 10 years.

 

Guess what? New plugs and all seems good. Went out and pushed it. The car was smooth and the CEL never flashed.

I think I fouled the plugs with the Seafoam. I canceled the the gasket order. Hopefully it's not the gasket, because then the issue will come back.

I really appreciate all the help you all have given me.

 

@04WDPSeDaN
No disrespect intended. I have done my time in the parts stores and as a tech. Have been for the past 8.
I will say since the plugs have fixed the problems there isnt much more reason to talk about this. I do agree with everything you said to btw. But even you have to have seen that the odds of a fuel injector causing a mis fire is a lot less common than a plug or coil. Especially on a p03xx code. I was simply trying to diagnose the cheapest option first before jumping to fuel being the problem.

OP Im glad to hear the car is back up and running alright! Def hit up that oil change and snag the PCV at the same time. 3 bucks helps in the long run. Check the plugs in another few thousand miles for oil around the tops or in the spark plug tubes. Otherwise. Carry ON!

 

That's not what happened, zero chance of that happening. There's very, very little carbon in the combustion chambers or even intake manifold. Most of it is superficial, just enough to color the aluminum. You could scrape all of the carbon out of the entire intake msnifold and scrape it out if every combustion chamber and set the "pile" on top of one piston and it would not be anywhere close to enough to bend a rod.

What happened is whoever did it screwed up and hydrolocked your engine. This is why you don't do top end engine cleaners. It's 100% unnecessary with today's engine management (DI excluded) and today's fuels. There is nothing that could get dirty enough to affect performance.

 

Seeing the plugs it's easy to see what happened. The coils were grounding out through the oil to the tubes. I'll bet money this is a temporary fix until they get saturated again.

Don't worry about what the combustion chamber side of the plugs look like. You had a misfire and it doesn't matter that they look fouled. They will always look fouled if the car was misfiring at the time the plugs were pulled. I bet if they are pulled right now they would show normal combustion.

I have no doubt that Seafoam will foul plugs but it's not the kind of fouling that stays around. They will clean up with a couple full throttle pulls. This is what happens with this crap top engine cleaner stuff. The engine studders and misfires because you're feeding so much into it. You see smoke out the exhaust which you want to believe is it cleaning the engine but it's only the Seafoam burning after all, you're way rich of stoich at this point. Then you stop and the car runs much better since you're not shoving this crap in it. Now your plugs are partially fouled. Not from any so called crap that's been cleaned but from the Seafoam itself. It runs 90% as good as it did before. You take it out and do a few full throttle pulls and all of a sudden Seafoam is magic. It totally restored lost power. I'm actuality you restored power back to where it was before the Seafoam.