1994 idle drops

[Rizin84]

i got a 1994 mercury cougar with a 4.6 Idle fluctutes and shakes at start up goes away when warm and intermittantly idle fluctuates with ac and shakes when coming to a stop also noticed voltage gauge fluctuates when this is happening. Replaced idle control valve and cleaned maf sensor. Still having problems..

[ronaldk]

one of your coil packs could have problem,you could need spark plugs and / or wires.I assume your not coding? I would also check for vac leaks

[Rizin84]

i put in new plug and wires about eight thousand miles ago i did have a code it was a p0340 camshaft position sensor i put in a new camshaft sensor. The code cleared but does come on during long trips. I will look into the coil packs thanks

[ronaldk]

I don't know if ford is using same type of sys to help cps determine compression stroke vs exhaust stroke as saturn vehs but if they do one of those coil packs probably are your problem. In 97 saturn my son bought it was coding on and off cps so we changed cps but I found out that #1 & #4 cyl on coil energized at same time then #2 & #3 at same time, under #4 in coil pack is a sensor that judges resistance diff between 1&4. because cyl under pressure (compression stroke) has higher resistance it knows that cyl is on compress stroke not exhaust and if coil pack,wires,or spark plug cause wrong resistance on #4 veh codes you guessed it cps! I am not saying thats for sure your problem but since you have one coil pack for each bank of 4 cylinders it would be a question to ask dealer serv dept or maybe auto parts store you trust to have that knowledge, do my coil packs check resistance between firing cylinders? maybe someone here will chime in if they know. It took me weeks to figure that system was being used on that saturn. They really dont want car owners to fix there own stuff. maybe this helps you. Let me know how it goes good luck