Car has had a rough idle ever since we bought it 1.5 years ago. 112,000 miles on it. Tranny was replaced by acura dealership right before we bought it. 90,000 miles on it when we bought it. 2002 CL-type S. I have replaced the IAC valve and cleaned EGR valve. PCV valve was checked and working fine. I have used Two applications of Sea Foam since we've owned the car and that did not fix the problem. I have heard to try to replace the O2 sensor, but not sure on that yet. Sometimes the warning lights come on (Check engine, VSA, and !) all three at the same time, and the car throws the P0172 code. "System too rich bank 1." The car has a long tube cold air intake that I put on. Idled rough before this addition. Filter on it is clean. I have sprayed mass air flow sensor cleaner in the intake (removed cold air intake and opened air valves) and all around that area and sprayed all electrical connections that I could find with contact cleaner. Intake looked pretty clean to begin with. If I clear the code it doesn't usually come back on right away. The warning lights are intermittent, and can go off by themselves during the same trip. Only the check engine light tends to stay on longer. The other two lights (VSA and !) tend to turn off earlier in a driving cycle. I have the acura paper copy service manual for reference. Car runs fine at higher RPM's, but has the usual stumble when letting off throttle (have heard that this is the torque converter).

 

bump

 

Where are you located at?

 

hm.. have you reset the ecu (pull the power for 10 mins and then reconnect and let it idle for 10-15 min) and have you touched the idle screw (i believe it's on the throttle body)??

 

Located in wisconsin. I can check the idle screw. I have not touched it on purpose. I can also disconnect the power, but the battery did go dead and she has gotten a new one since then, so the power was disconnected for at least ten minutes then. I can try that again, though. Thanks for the tips. Keep them coming if you have any ideas.

 

aaah, just thought you'd be nearby within the bay area & could probably could've lent a hand...anyways, sounds like something I encountered myself last week (rough idle, cel on, etc) turns out lines 2,3,4, & 5 were misfiring & that for some reason within 90K-100K the coils begin to go bad (or so I was told)...after purchasing new coils along with new plugs, all is well...(mine has about a little over 119K miles)

 

ouch, that's a lot of coils to buy! My lincoln navigator is giving me troubles with coils as well, but it's because the factory plastic clips that hold the coil to the vehicle wiring all broke off from the heat and age (they are part of the vehicle wiring, not the coil). Now, nothing is holding the connection tight. I have literally one inch of slack, so even taping them with electrical tape doesn't work well. They throw misfire codes and that cylinder will run rough until I get back into the motor and mess with the connection of that specific coil. Pain in the ass, as they are under plates that are bolted down and you have to remove other stuff to even get to the top of the head to work on them.

 

I will try to play with the idle screw (if I can find it). I looked the other day while I was in a hurry working on other stuff, but couldn't find it. I will bust out the service manual and find out exactly where it is. I don't believe that the idle is low, though. When I measured the resistance of coils in my truck, the supposed bad ones didn't measure any different than the new ones. However, when I installed them, the truck did run more smoothly and the CEL (check engine light) went off. It still runs rough and I get the CEL when one of those darn coil connections loses contact. Her Acura is different, though. Only idles rough, no loss of power during accelleration. Just rough idle/hesitation while at low rpm's (when coasting at lower speeds and idling).

 

That doesnt sound like coils IMO...
It sounds more like a O2 sensor problem..

I'm sure that the sensors have never been replaced since its not something that many people replace..

I did have a similar problem with my CLS. I replaced the sensors when I got it as it was throwing a cat code. Later turned out I didnt even have a cat.
So 2 new sensors for no need.

HOWEVER, the front one went bad and was throwing a code. On and off. Was a bit sluggish.

Changed that sensor under "warranty" since it went bad and installed it. Never had a problem again.

The difference is that I have a CLS6 and I keep it in the high revs pretty often so it was not that noticeable.



I would try to change the O2 sensors, disconnect the battery for a while, start it up and drive it for a while. See how it behaves.

 

Well, how do I know exactly which o2 sensor to replace? They aren't cheap. I think the service manual said to replace the one that is closer to the front of the car. I did heat them both up with a hand torch with MAP gas. They looked clean to me and there were no deposits on them at all even before I heated them.

 

Has anyone checked out what the details of TSB # 307 are for the 3.2 cl? I can't find the details anywhere.

 

This exact same thing is happening to me but I unplug my battery and it doesnt come up for another month or so.

Also the car doesnt feel any different no miss or nothing Idles fine too

Comes on during

stop once
high way twice
and street going 40mph once

I have no suggestion on what it is and havent check the code but theres some more info to find out whats wrong because I want to know too

 

I've also got this problem with my 03 CL-S that I bought a few months back. I've only got 70,000 miles on the car. Seems to pull smooth and strong at mid to high rpms, but at idle and just off idle there is what seems to be a "miss". I've replaced the spark plugs, but nothing else yet. Hopefully it doesn't come down to coil packs or something else that's mildly expensive. Heck I bought the Honda in the first place so I wouldn't have to replace failing parts (other than normal wear parts) until 200,000k miles! Are coil packs considered a normal wear item? This is my first vehicle with them.

J

 

our coil packs usually last until about 100k thats when people start replacing them. but the op's problem seems to be the 02 sensor. theres a reason why its throwing the bank 1 code and usually its taking off measurements thats why your car is running like that. Its not getting the correct a/f readings. also check your cat (clogged cat), bent exhaust piping

 

I'm new to these cars, but if you haven't checked your plugs yet I would try that. I recently hit 108k on my CL-S I just bought. I was having problems at lower speeds, and assumed I would pull out old factory original plugs... I was surprised to see some Champion plugs with the ceramic section closest to the igniter burned. Replaced with NGK iridium lazers and it was like a different car. Good luck.