PCV Valve? Idling Rough/High

[MattTee]

2001 PT. Changed the valve cover gasket last night. Put everything back together (correctly). Started car, it immediately shot up to 4,000 RPM, then went back down to 1500-2000, but is idling horribly. Anyway, when I was putting it back together, I noticed the previous owner had broken the PCV valve at the thread where it screws into the valve cover, but I put it back the way they had it rigged. Anyway, can the PCV valve being jacked up really cause this much trouble? I took the hose off and checked for vacuum at the manifold there, etc.

Ideas?

Thanks a ton.

[CREWZIN]

This is a question and answer from PT Do-It-Yourself.net

I have a 2004 BE PT with 89k miles. My PT has been idling funny for about two months, both in park and drive. It will idle smooth at around 800rpms than drop to about 500rpms, sometimes even stalling. I recently changed the plugs and wires to see if this would help, but it did not. I have a mechanical background and thought maybe the PCV valve. - from Florida.

If this is the original PCV valve it's overdue for replacement. If not, PCV valves are inexpensive and easy to replace therefore you can give it a try however a faulty valve and accompanying vacuum issue will usually cause a rolling or somewhat rough idle. Once tested and eliminated or replaced, if you still have a low idle condition continue reading.

The IAC motor (inside the throttle body) controls idle using a variety of inputs through the PCM. Rough idle and stalling most often occur when the idle speed drops below normal rpm. This can be caused by an issue with any one of the inputs which control idle through the PCM or a problem with the IAC motor.

The IAC Valve/motor.

[MattTee]

Nevermind...nothing to see here...move along. It'd help if I connected the EGR pipe back up, wouldn't it? First rule of me and car repair - I will always for get SOMETHING and swear up and down all day I didn't.

[CREWZIN]

Glad it was an easy fix.

[Hooligan]

MattTee, thanks for coming back and letting us know the why and wherefores. Sorry you had to learn the way many of us had/have to learn.