My wifes crown vic is driving me nuts. Most of the time it runs fine, once in a while it throws a check engine light and runs really bad. Just latley when at an idle it just quits. No codes! I neplaced the plugs, wires, fuel filter and so far one coil pack. I even disconected the battery and hooked it back up to try and get it to reset. HELP!! This thing is as nutty as my Super Coupe. Thanks Tim

 

First, never d/c the battery when the Engine Light is on. It just erases the code that someone will need to start diagnosing your problem. Once the light comes back on, find a way of checking the code (autoparts store, friendly neighborhood mechanic, etc) then post here again with that DTC. A couple of things that can cause rough idle and stall: EGR valve stuck open, either through a mechanical fault in the valve or a faulty EGR vacuum solenoid. Vacuum or air leaks which could be found anywhere between the air filter housing (MAF sensor)all the way to the intake manifold gaskets. Intermittantly stuck open pcv valve or detiorated(sp?) pcv hoses and tubes; "ESPECIALLY" look at the pcv tube at the elbow where it connects to the throttle body. The soft rubber hose parts go bad often because of the oil droplets and vapor from the pcv. Rubber doesn't get along too well with oil over time.

If you find a way to pull codes, post again.

Good luck,
Victor