Anyone know how to get the idle down on a 99 neon 2.0 with an automatic? My car idles around 1200 rpms and when i'm stopped in traffic I can feel it wanting to go. I was checking on the throttle body to see if there is any kind of screw or anything to adjust, but I couldn't see anything. Thanks.

 

Idle is controlled by the IAC (Idle Air Control), operated by the PCM. The IAC on the throttlebody has a tendency to start sticking after a while. Best bet is to take off the entire TB, get some carb cleaner, rags, and q-tips and get it shiny again, inside and out.

Idle will tend to be a little higher if you have the a/c on, but 1200 is a bit out of the normal range...

Best of luck!

 

Im also having the same problem
Even when my ac/heater is off it idles high
I Do you have a CAI if that makes any difference
Would adjusting the idle adjustments on the throttle body make any difference

 

There are no idle adjustments on the throttlebody. The PCM maintains idle rpm in a programmed band by using the IAC, which has 4 speeds (high and low, up and down). If the IAC is getting gummed up, it will be slow to respond and idle will either hang or the car will die, depending on where the valve is and where it is supposed to be... If the idle rpm does not reach the programmed band within a certain time period, or the IAC does not respond at all, the PCM will throw a code and the CEL will be lit. Chysler was apparently very generous with the allowed amount of time since this is a pretty common problem on the Neon and no one ever seems to get a CEL for it...

If the IAC is working properly and you are still getting the high rpm's, you probably have a small vacuum leak somewhere. Again, Chysler was a little generous with the settings since a vacuum leak should cause the CEL to come on. Another fairly common problem on the Neon. You can check for vacuum leaks with a spray bottle (heck, even a garden hose), just spray around all the hoses and sealing points for the intake manifold and TB, and the idle will drop when the water gets in the leak location.

 

i had a custom cold air intake i made for the drag strip, and my car would idle very high at certain times, normal the rest, that was til i put the air filter on. (when i drag, i took the filter off) car runs great with it on, off it idles high, maybe too much air? or too cold of air?

 

Yeah the filter actually does affect it some when put on my cai my idle jumped 200 or 300 rpms (cant honestly remeber exactly) it never really affected anything so i knd of forgot about it...

 

My MTX has always idled at 800 RPM. Clean the TB real good and you should be fine.

 

Also a thing to look for is a vacuum leak. They can run idles up some.

 

Think polishing up my TB will cure this:

Car idles high (no tach, but guessing about 1400rpm), and I dont like when it goes into gear at that high of rpm. Sometimes it will go kinda low (I can feel it in the brake pedal with the auto that it goes low) but it may be the cooling fans. Ill be upgrading the big 3 to 4awg and im putting a system in it, but would cleaning TB and IAC be the best place to start? 200k km 95

 

check your vacuum lines and codes... my sisters idled around 1400...she had to get the ASI motor replaced and that got it down to 1200...and then it took me like 2 months to figure out that the reason why it was at 1200 was because the brake booster was bad... but check the vacuum lines and codes...