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So at the end of last summer my 04 Auto TL (126k) was having sluggish acceleration. I replaced the APP sensor and never had the issue again but it never really got warm again as it was the end of summer. Haven't had a single instance of sluggish acceleration until last week.
Last week it was pretty warm out and sure enough, it did it again. Car feels like it has 1/2 the power it is supposed to throughout the entire driving range. Hasn't happened again to that extent but it does occasionally feel sluggish randomly. It seems more likely to happen when it is warm out.
The other thing that I noticed is when I do get on the gas it sometimes smells like rotten eggs. I was told awhile ago that this means you could possibly have a clogged cat. I had the same sluggish acceleration problem with my grand prix which had a clogged cat. Once I replaced the clogged cat, I could not believe how much better the car drove. It literally felt like it had a 50% power increase. I should also note that about 2.5 years ago my CEL came on for an oxygen sensor. I reset the light and it has never came back on, not sure if that is related but I thought I would mention it.
Oil level is fine and always changed on time
Tranny shifts smoothly, 3x3 done often with Amsoil and 3rd/4th switches replaced
Air filter clean
Plugs replaced 15miles ago with OEM NGKs (retorqued to spec last oil change)
Shell 93 octance
Can of Seafoam in gas every 6months or so
So what do you think it is? I am leaning towards a clogged cat or bad O2 sensor at this point. These cats are expensive so I don't want to just buy one and hope that it is the problem. Plus, don't these cars have three? How am I supposed to know which one it is?
I am going to reset the ECU but I'm pretty sure it wont help.
Other mentioned is could be a EGR valve or IAT. I hate just throwing parts at a unknown problem.
Thoughts?
Last edited by thegipper; May 11, 2015 at 08:17 AM.
If you're not getting a MIL, it's unlikely that either of the 2 primary cats are clogged or that it's a bad O2 sensor. The 3rd cat could still be clogged though.
If you have an OBD tool, you can monitor the 2nd (downstream) O2 sensors' voltage. It should remain fairly steady at ~ 0.5V
I do have one of those bluetooth obd2 adapters and the Torque app. I think you can check it with that.
Is there any way to check the 3rd cat?
Yeah, you can check the o2 sensors with Torque. Only way to check the 3rd cat is with an IR gun (outlet temp should be higher ~400C than the inlet temp ~200C IIRC) or by pulling it and physically/visually checking it.
Yeah, you can check the o2 sensors with Torque. Only way to check the 3rd cat is with an IR gun (outlet temp should be higher ~400C than the inlet temp ~200C IIRC) or by pulling it and physically/visually checking it.
When you say to check the outlet/inlet temp do I just point the IR gun at round part of the cat on each side (inlet side/outlet side)? And do you just check it at idle after the car is warmed up? What would be an example of a bad one (500C outlet? 600C outlet?)
Also, how hard is it to just unbolt the cat and visually inspect it? What would you look for that tells you its bad?
Yeah, give the cat time to warm up, dunno, maybe 5 minutes? Then have someone run the engine to 1500 rpms.
And then point the gun at both ends taking note of the reading. If the outlet temp isn't higher than the inlet temp (end nearest the engine), then that's a sign it's blocked/clogged.
Eric the Car guy has a good video on using an IR gun to check the cats.
I'm not certain, but I think the 3rd cat is just bolt off/bolt on. You should be able to look down inside and see if the internal material has come apart/loose to block the passage way.
If you're not getting a MIL, it's unlikely that either of the 2 primary cats are clogged or that it's a bad O2 sensor. The 3rd cat could still be clogged though.
If you have an OBD tool, you can monitor the 2nd (downstream) O2 sensors' voltage. It should remain fairly steady at ~ 0.5V
OK so I checked this omw home. I was getting readings as low as 0.0 all the way up .8
it was at 0 when I was coasting and as high as .8 when accelarating. It wasn't really ever staying around .5, does that mean it's bad?
I also reset the ecu which I can tell improved the feel of the car. Only time will tell if it fixes the sluggish problem, I doubt a simple ecu reset will fix the problem but who knows.
I'll borrow my buddies infrared gun and test the cat hopefully this week.
OK so I checked this omw home. I was getting readings as low as 0.0 all the way up .8
it was at 0 when I was coasting and as high as .8 when accelarating. It wasn't really ever staying around .5, does that mean it's bad?
I also reset the ecu which I can tell improved the feel of the car. Only time will tell if it fixes the sluggish problem, I doubt a simple ecu reset will fix the problem but who knows.
I'll borrow my buddies infrared gun and test the cat hopefully this week.
That sounds like you were measuring the upstream O2 sensor, not the downstream 02 sensor....
You need to add displays for:
O2 Volts bank 1, sensor 2
O2 Volts bank 2, sensor 2
The display headers should read:
O2 1x2
O2 2x2
Last edited by nfnsquared; May 11, 2015 at 06:34 PM.
Well I rechecked and this is what I found: For most of the time it would stay at about .6v but it usually would drop to zero when I would let off the gas and go as high as .9v when I would be on the gas. Sometimes it would still fluctuate all over the place. I still doubt it's a bad O2 but thought I would share.
Well I rechecked and this is what I found: For most of the time it would stay at about .6v but it usually would drop to zero when I would let off the gas and go as high as .9v when I would be on the gas. Sometimes it would still fluctuate all over the place. I still doubt it's a bad O2 but thought I would share.
When you get off the gas pedal the car cuts fuel to help save fuel and apply engine braking hence it dropping to 0. Get a IR temp gun from habor freight, it's $20.
When you get off the gas pedal the car cuts fuel to help save fuel and apply engine braking hence it dropping to 0. Get a IR temp gun from habor freight, it's $20.
I'm going to check that next. My boss has a IR gun I can borrow.
So I still haven't had time to check the CAT with a infrared gun but yesterday when I had to get on it, I noticed the check engine icon was flashing on my car. First time I have ever seen that happen. The car accelerated like normal and wasn't showing any signs that anything was wrong.
After about 10 seconds, the flashing light went off. I pulled over and scanned the car using my Torque app and this is what I found.
I kind of figured it was some kind of misfire because of the flashing light. So I drove home like normal without issue.
So, would a plugged cat cause misfires? The plugs are only like 15k miles old (recently retorqued) so I doubt the plugs are bad.
Thoughts?
Last edited by thegipper; May 26, 2015 at 07:28 AM.
Im having the same issues I check my app sensor clean the egr reset the Ecu drive normal no misfire. I did noticed on one plug look white/grey haze could be running lean
Is there a way to test the coil packs? I'm assuming because it was cylinder #1 and #5, those are the ones that need to be checked? Again, it only did it on WOT and went away right away.
I picked up the infrared gun so I'll check the CAT tonight after work and report back.
Is there a way to test the coil packs? I'm assuming because it was cylinder #1 and #5, those are the ones that need to be checked? Again, it only did it on WOT and went away right away.
I picked up the infrared gun so I'll check the CAT tonight after work and report back.
sounding more and more like a clogged/dirty cat. Take a whole can of seafoam and put it through the vacuum line that's on the intake manifold after the throttle body by slowly having it sucked into the engine. it's best to do it with 2 people, one to keep the RPMs at around 2K. After half the bottle is through the car, shut off the engine and let it sit for 5 minutes and repeat.
The vac line is the rubber hose 3-4 inches long with a pressure clip on the end of it, it attaches to the top at a 90 degree angle by where the ACURA VTEC is written. Put on a new clear hose onto the end coming out of the intake manifold and dip it into the can slowly.
sounding more and more like a clogged/dirty cat. Take a whole can of seafoam and put it through the vacuum line that's on the intake manifold after the throttle body by slowly having it sucked into the engine. it's best to do it with 2 people, one to keep the RPMs at around 2K. After half the bottle is through the car, shut off the engine and let it sit for 5 minutes and repeat.
The vac line is the rubber hose 3-4 inches long with a pressure clip on the end of it, it attaches to the top at a 90 degree angle by where the ACURA VTEC is written. Put on a new clear hose onto the end coming out of the intake manifold and dip it into the can slowly.
Won't this just make the CAT even more clogged?
And I'm assuming a misfire can happen if the cat is clogged based on some reports that I've read on a couple other forums. Something to do with the exhaust gases not clearing the combustion chamber and not allowing clean ignition of the fresh fuel/air.
Last edited by thegipper; May 26, 2015 at 01:36 PM.
Well I thought I would update this post. I replaced the rear CAT with a walker replacement one off of Rock-Auto.
Anyone planning on replacing this rear cat that lives in the rust belt should plan on this job being a PITA. I had to cut all 6 bolts off as they were rusted beyond use. Using a cut off disk on an angle grinder in such a tight area without destroying the exhaust pipe itself and many other things is quite the task.
Either way I did get it off and put the new one on with new gaskets.
So far I cannot tell any difference in performance. The old one actually didn't look that bad on the inside at all. I haven't had the "sluggish acceleration" experience yet but it only happens once in a great while anyways so I guess only time will tell.
Think I'm going to clean the EGR valve next and possibly run the seafoam through the vacuum lines just for good measure.
I have this problem from time to time too and have jumped through some of the same hoops. (replaced APP sensor, high flow cats, 3rd cat delete, newish plugs, etc)
I don't have any lights/codes and Torque does not pull up anything - certainly no cylinder misfires.
Just randomly, it feels like I accidentally got into my wifes 4cyl Pontiac G6
Wish I had an answer, just here sharing in the frustration lol.
What kind of battery are you using? I remember a thread a while back where some members were reporting sluggish acceleration with Optima batteries in warm weather.
I have this problem from time to time too and have jumped through some of the same hoops. (replaced APP sensor, high flow cats, 3rd cat delete, newish plugs, etc)
I don't have any lights/codes and Torque does not pull up anything - certainly no cylinder misfires.
Just randomly, it feels like I accidentally got into my wifes 4cyl Pontiac G6
Wish I had an answer, just here sharing in the frustration lol.
Yeah me too. It is pretty random and it just feels like it has 1/2 the torque that it normally does. I am going to do the Seafoam in the vacuum line hopefully tonight.
Originally Posted by 3gstealth
What kind of battery are you using? I remember a thread a while back where some members were reporting sluggish acceleration with Optima batteries in warm weather.
It's not an optima, I made that mistake with my Grand prix a couple years ago. Worst battery I have ever owned.
I'm running a 2year oldish Auto Craft Gold battery.
I am having the same problem with my 06 with 123K. Sluggish acceleration with more than a minor load, more noticeable with AC on. Just got real hot her in VA. Thought is was bad gas, refilled tank, no help. Engine runs smooth at idle, no trouble lights, no exhaust odors. My son has my Scanner, not available to check for preliminary codes, how do I reset the ECU? Any help?
"turn the key to the second position make sure everything is off like radio ac and so on... take it out put it back in and then again to the second position and press the gas pedal for like 30 seconds... i do it for a minute just to make sure. Then simply turn of take the key out put it in and turn the car on and there you go"
You're welcome.
Figure I'll update the situation with my car. So far I haven't had any instances of sluggish acceleration since changing my 3rd cat but I also did the Seafoam in the vacuum line thing. I'll update as necessary.
It's been a little over a month and no instances of sluggish acceleration. I think the 3rd CAT was the problem.
I also replaced my air filter this weekend which hasn't been changed in well over a year (oops). The old one was pretty nasty. I can noticeably tell a difference in performance since changing it. It's not night and day but wow, it must have been pretty plugged.
I am usually meticulous about maintenance but this time I forgot.
It's not a clogged cat. A clogged cat will barely allow the engine to hit redline even in neutral or first gear. This is not even close to a clogged cat. It's especially rare for the 3rd cat to come apart since it doesn't see the same high temps as the others.
Optimas suck, since the buyout 6-7 years ago they're living on their old reputation. Sears Diehard Platinum are about the best bang for the buck if you're looking at an AGM battery.
Some TLs hate hot weather and have more than the normal power loss in hot weather as all cars do. Mine did this since its second summer in '07. I've now fixed it but it took years and it was more than one thing. Those having heat issues can check out my old threads on this issue if you want.
