JFutrelle

Hey guys. I realize that there are plenty of "rough idle" posts out there, and plenty of "stop posting idle issues" posts as well. This issue, however, is really freaking me out and I'm not sure what to do.

Car:
2004 Acura TL
175,000 Miles
Timing belt changed at 120k

Issues:
About two weeks ago, my car starts acting funny. It idles like its being choked. If I'm sitting at a traffic light, the rpm will drop down to below 500rpm, and sometimes will cut off. Makes a loud clacking sound when I stomp the gas from a stop, just struggles if I go easy. Once underway, particularly at highway speeds, it makes a similar sound when I give it gas over about 2k rpm(sounds similar, but is very rapid. Sounds like when you rev up a diesel F-350). Drives reasonably normal at low speeds(20-50mph) to the point where you wouldn't know anything was wrong (apart from the tach jumping around).

Pulled codes. All cylinders are misfiring. Mechanic suggested bad gas. I had bought gas from a less than reputable gas station(GoGas) about 10 minutes before the issue started happening. Between the coincidence, and the fact that it meant I wouldn't have to do anything expensive, I went with it. I only put a half-tank of the "crap gas" in originally. I went to BP and topped off with premium. I have since gone through that full tank, filled up again, and gone halfway through the current tank.

Needless to say, I'm starting to have my doubts. I don't feel like bad gas would cause the loud noises at high rpm. Furthermore, the idle drop seems to be rhythmic. Once the car has run for a while and is sitting, the drop in idle seems to happen on a regular basis (for 2 seconds about every 10 seconds).

Sorry for the novel. Anyone have any ideas on this? Per a couple of other threads, I'm going to grab some injector cleaner and try that while everyone is marinating on this, but not holding my breath.

Also, can we rule anything out from the codes? For instance, would a hose leak issue throw an O2 code?

Thanks,
John

justnspace

iTrader: (1)

*edit Go get the codes read from the auto store!!!! record the code letter and numbers and report back to us!


Hey John!

lets see if we can get you squared away. I'm assuming the car is an automatic.
Have you checked the oil level lately?
thumbs up if oil is at full line.

2nd, if you havent already, clear the codes by pulling the negative terminal from the battery for a few seconds.

this will reset the computer and clear anything that was stored.

lastly; by your knowledge has it ever been over heated?

JFutrelle

Thanks for the quick reply. First off, I will have to go back to the shop for any new codes, but codes were CL01-CL06.

My TL is an automatic. Oil level is good.

Cleared the codes. Drove it around for about 10 minutes after. CEL hasn't come back on yet, but it's still running like garbage. My guess is it will be back on in the morning.

Never overheated during my ownership (purchased as 2nd owner in 2008).

nfnsquared

OP, who pulled the codes? And what is a CLxx code? Never seen that before?

Wonder if that gas station had some diesel fuel mixed into the tank by mistake? That happened to my cousin at Kwik Trip. The fuel delivery driver pumped some diesel into the wrong storage tank by mistake. My cousin was filling his truck as the diesel started to go into the wrong tank. He had mostly gas going into the truck gas tank, but some of the diesel made it in there as well. His truck started and ran, but there was something obviously wrong as he drove away from the station.

A lady who pulled up to the same pump about 15 minutes later didn't fare so well. By now, the fuel guy had emptied the full load of diesel into the tank and she unknowingly pumped mostly diesel into her car. It wouldn't even start.

Kudos to Kwik Trip, they picked up the tab to professional clean my cousin's fuel system and gave him a $200 gift card.

JFutrelle

CL is the code for cylinder misfire.

justnspace

iTrader: (1)

^who checked the codes?
CL01-CL06 arent valid codes.
I dont even know what those mean.

JFutrelle

Sorry, should have been more specific. Actual codes were:

P1301
P1302
P1303
P1304
P1305
P1306

pbook4g5

Well it sounds fuel related (fuel filter or injectors), but it could also be mechanical. I doubt all your spark plugs and/or coils would crap out at the same time, but I'd pull the front plugs to at least look at them and see if they seem ok.

It could have jumped time, which would cause misfires like this, but it would also cause other issues. Could be a bad crankshaft position sensor, but that would also throw a separate code so I don't think thats it.

I'd dump some octane booster/fuel system cleaner in your tank and see what happens as you run through a tank of good, premium gas.

JFutrelle

I'm baffled. If it was timing, wouldn't the shuttering be pretty rapid, even at low rpm, rather than happening every 5-10 seconds? I would expect that to be more of a rapid ticking.

I also read on a few forums that one cylinder misfiring can throw codes for all of them. If that is the case, maybe it is a coil or plug.

Didn't use octane booster, but added fuel injector cleaner last night. Going to give it a few days then start poking around.

I'll keep you posted.

crbnfbr

iTrader: (1)

That sounds real familiar to when I took off my manifold cover, and forgot to reconnect the plug that actuates the dual plenum intake.

HondaTech85

Check the timing belt. My tensioner failed and caused the timing to jump 2 teeth on the rear camshaft. I replaced my timing belt and tensioner with OEM parts less than 20k miles back. The tensioner lasted 20 months. Only the second time I have seen this happen but is not that uncommon.

nfnsquared

JFutrelle

Bingo. Bad timing belt tensioner. Jumped 3 teeth on the front bank, so it was running super feisty. While digging around, I also figured out that the shop that did my last timing belt service bondo'd a crack in my water pump and re-installed the same one. Good to know.

Thanks for the help,
John

I hate cars

Glad you found it. Hopefully there's no valve to piston contact. I guess if they installed a badly repaired cracked water pump it's not a surprise that the tensioner was not replaced (was it supposed to be replaced?). On the bright side, it was the cam and not the crank that jumped time.

Keep us updated with the status once it's repaired. I'm curious to see if it can be a few teeth off and not damage valves.

pbook4g5

One tooth maybe, two is probably pushing it. I think three is when its getting damn close to valve+piston friendship time.

JFutrelle

Sorry for the delayed reply, but wanted to give it some time before reporting. It was indeed 3 teeth and, no, the crappy shop didn't replace the tensioner.

New timing belt, tensioner, and water pump. Good to go. No valve damage, and it runs smoother than ever during my ownership (2nd owner). I'm adding a link to a video I took of the sound it was making while under power at highway cruising speed. I'm really surprised that there wasn't any major damage.

Thanks everyone for your help,
John

JFutrelle

Also worth noting that I drove it for a month like this while trying to get it diagnosed, including a 300 mile road trip.

polobunny

You must be so happy there's no damage. What the heck man.

JFutrelle

You have NO idea. The thing is probably only worth about $6k, so probably would have had to just scrap it. Happy to be staying in no car payment land for another few years.

Other than this(which was my old mechanic's fault), a rat chewing through my knock sensor cable (see other threads on this random but common occurrence), and the dash cracking like a spider web(ditto), it's been a great car so far.

My wife still has me beat. She's still driving the 1996 Honda Civic she bought new when she was 16. Here's hoping my Acura lasts 20 years.

John

polobunny

Until the AT transmission went to crap last year, my mom was driving a 1997 Civix DX. I'm sure it would still be running fine for many more year if it had been a MT. Honda are good cars.