my 1996 GL ATX ideling very wierd, when i start the car after it sat there allnight sometimes the RPM will jump to 1500rpm and start increasing to 2500rpm and just sit there. when i put it in drive after that it jumps back down to like 1000 or 1500rpm.
also when i drive around and come to stop sign or stop light sometimes it had very hard time ideling and sometimes it even stalls.
can some one please tell me what could cause this. I changed fuel filter, O2 sensor last year, i have aftermarket air intake(some people say this could cause this w/o resseting my computer).
I bought new PCV valve and bou tto change it today. would PCV do any difference?
please help bc its gettign very annoying and once i almost got into accident bc my car stalled while i was driving downtown and my wheel locked and break booster turned off.
PLEASE HELP

PCV valve might help... Do you have a CEL on?

Generally if you have an idle problem, it has something to do with the IAC valve... Which is located on the intake manifold below the throttle body, its kind of a PITA to get to on the zetec, you have to remove the air intake assembly to even see it from the top of the engine bay... Either way, try cleaning that, replace your PCV... and if you have a CEL on get the code scanned... You might also need a new TPS.

Idle problems also can be caused by vaccume leaks.

TPS or IAC would me my guess.