car problems - PLEASE READ!!!

[bnichols9883]

For the past few days I have been having some problems with my wifes PT cruiser. It naturally idles around 1800 RPM, here lately when you start the car it jumps to 1800, like always, then drops to 500RPM then bumps back to normal. This cycle continues many times ultimately either becoming normal and driving fine after 2 min, or it dies then I restart it and begin the process. I dont know what could be causing this, my wife told me this morning that it now has a funny smell. I have not checked on that, and it may be all in her head. But if anyone has any insight on this topic I would greatly appreciate it.

[Moppie]

It should have a warm idle speed of around 700rpm, and a cold idle if around 1800rpm that will slowly come down to 700rpm as the car warms up.

[gremlin96]

ask her if it smells like rotton eggs. if so its the cat converter cloging. its a easy check. idle up the car high stand behind it and smell. you would be shocked at how many are running around with cloging cats.

[shorod]

Does it idle smoothly, or is it a bit rough? If smooth, then the issue might just be the idle air control (IAC) servo that is wearing out. Chrysler OBD-II systems are pretty good and a professional grade scan tool can easily test out the IAC servo. There is a feature that allows the scan tool user to request a certain engine speed. The PCM will use the IAC to attempt to attain the requested engine speed, displaying both the desired speed as well as the engine speed.

If the idle is rough, then you probably have a vacuum leak or a misfire. When was the last tune up performed? Also, in case someone recently checked the air filter (maybe during an oil change) it's possible they didn't get the intake air tube installed properly and/or tightened correctly. That could let in unmetered air, effectively acting like a vacuum leak. If there is a vacuum leak/misfire, it can cause a foul odor from the exhaust and if ignored long enough, eventually cause the catalytic converters to overheat and plug up.

The OBD-II system has a lot of emissions monitors though, including catalyst efficiency codes. If the converts are substantially plugged, a code should be set with a flashing check engine light.

-Rod