View Full Version : P0411 & Rough Idle

11-06-09, 02:42 PM
2001 non-sport, 166,000 miles

- P0411 code several times a week
- Rough idle when started cold
- No issues once the engine was warm

- Replaced MAF sensor

One trigger for the P0411 code is failure to detect a lean condition during a cold start as it should with the extra air introduced by the secondary air injection system. During a cold start the MAF sensor must have been mis-guiding the computer causing an unexpected fuel-air ratio as measured by the O2 sensors. Once the car warmed up and closed-loop control was established the car ran fine.

11-08-09, 10:46 AM
my catera did this rough idle the other day after it was warm! check engine and t/c light poped on and car had NO power to drive. so I shut off and restarted and it was fine.. think it could be same issue? I have yet to have the c/e light code pulled.

12-09-09, 12:06 AM
I think you will find that your idle control valve is full of carbon and your breather pipes to the plenum chamber are probably full of crap as well...All you have to do is locate the idle control valve,remove and diamantle it and give it a good old clean and do the same with the breathers that should clear up your rough idle problem....:thumbsup: