My car:
1998 Mystique
2.5 V6
ATX
~55k miles
Problem:
Recently, like for the past few weeeks (5-6) i've noticed that my car's idle speed has been sitting at like 500 RPM versus around 700 before. Also when i rev it up while idiling then let it come down on its own, the engine speed drops real low, like 300 or lower and sounds like its gonna die...however, it always catches itself, and has not died yet. Then a few days ago, the car started idiling real low, like 200, on its own...that freaked me out, so i shut her down. Now idle has returned to approx. 500 when i let it settle; when in "Park" or "Drive."
What i've attempted so far:
-I cleaned the IAT and MAF sensors with some non-residue electrical cleaner (basically for the MAF i just sprayed it on, it looked really fragile, and i didn't want to break it)
-Checked the EGR valve. I applied vacuum to it at idle and the RPMs bog down real hard...which leads me to believe that it is functioning fine. Also idle speed doesn't change at all when i disconnect its vacuum line at idle.
Also, in a related matter, i have recently replaced the DPFE sensor (and hooked it all up correctly) with a black plastic one, just stating this as an fyi. The problem was there before and after DPFE replacement.
-I cleaned the IAC valve with carb cleaner. I used plenty of swabs and cleaner; and made sure that the rod/valve moved fully, and that it was all clean. To test it out, i disconnected it at idle and the car almost stalled out... so i reconnected it quickly. This leads me to believe that the valve is functioning well.
-I have reset the pcm many times by disconnecting the battery for long periods of time, like over 10 min.
-I have also checked the vacuum lines at the EVR thing, around the EGR crap, the 2 lines on top of the UIM (the further front one actually comes out really easy)
- I just put in an SVT airbox with new filter, its all hooked up properly...anyway the problem existed before the new intake
...So, whats left to check?
Am i correct in assuming that if i had a vacuum leak that the idle would not just be lower, but rough as well?
I'm kinda confused, when i put my ear close to the PCV valve i could kinda hear rushing air at idle...could a bad PCV valve cause low idle?
Any and all help is greatly appreciated!
edit: Also, fyi, no CELs or warning lights of any kind.
Last edited by amarv12; 08/21/04 01:25 AM.
