Contour Enthusiasts Group Archives Forums General Troubleshooting Idle all over the place, what else can I do?

On tuesday of last week, it got really cold outside (below 20 degrees). I went out to start my car and the idle was going crazy. It would continuously rev up to 2000, and back down to around 200 rpms before it goes back up again. Sometimes the car would stall, but it would always start right back up if it did. When I pull up to a stoplight, and I am holding the brakes, the revs fall again and sometimes the engine stops. If I hold the gas, the car keeps running.

I took my car to Autozone and Advance Auto Parts who each read my engine codes. The codes told me that I have an Idle Air Control Underspeed Error and that bank 2 is lean and that I have misfires on cylinders 4,5, and 6. I also got about 6 different oxygen sensor codes.

I spent the next few days searching the forums to find out what to do.

I broke my right arm in November and just got out of my cast on Friday, January 9, 2004 so I couldn't work on my car until this weekend.

I had a lot of fun doing everything with my left had. Since I had the dealership change my Idle Air Control Valve back in October, I figured that shouldn't be the problem. I ended up changing my plugs and wires.

Tomorrow I plan on changing my PCV valve and Fuel Filter.


Is there anyting else that I should look at while under the hood tomorrow?

Had similsr problems and if I had caught it soon enough, all it would have been was a vaccum leak. Drove the car, with the same problems you are having for a couple of weeks, ended up at the stealership, UIM and LIM gaskets, MAF sensor and new IAC (IAC was first thing replaced, but with vaccum leak it went bad again) Check for vaccum leaks first! Codes for O2 sensors were initially coming up too, but they were fine. How many miles?

Thanks for the quick reply. I am at around 89,800 miles.

How do you check for vacuum leaks?

I was told to use carb cleaner. You can spray it around your Upper and lower intakes, look for bubbles. You can also hear a little hissing, and or see the carb cleaner dissappear. I would also spray around the pvc area, you will need a flashlight to look close enough. Also there is a vaccum hose that runs close to the pvc and back down along your fire wall. From what I have read in these forums, this is a common area for vaccum leaks. You may also want to read some of the How to's in reference to cleaning your MAF and IAC.

and or see the carb cleaner dissappear


This would be the carb cleaner being sucked into the "leak"

Try looking for the vacuum leak first, however, it could also be the TPS sensor.

My 98 LX is in the shop right now for the same issues. My car needs 2 oxygen sensors, both upper and lower intake manifold gaskets and a new fuel filter. I'm also having plugs and wires put in as well. So, if the things you've fixed aren't the problem, definetely check your LIM/UIM gaskets.

Also, this is my best friends auto shop so I know he isn't railing me on the work or saying there are extra problems and unlike the dealer, I'm there when he does the work and can see the diagnostics myself.

So again, if the problems you're fixing don't ultimately fix the BIG issues, check for vac leaks and the LIM/UIM gaskets..

Thanks for the help everybody. I will let you all know if I find out the solution.

first thing I'd do is to make sure your IAC is properly installed. the bottom mounting bolt is prone to breaking, and will cause an air leak causing the symptoms you describe.