My dad has a 1994 f150 with the 5.0 v8. Whenever you crank it the rpms and the idle fluctuate up and down. It is a real pain when you are trying to get out of a parking spot b/c turning the wheels sharply makes it worse and it usually cuts off.
It will even do it while in park.

I was told that this is a fairly common issue. Any advice would be greatly appreciated.

 

I had an idle problem too.....when I let off the gas the motor would drop down to 500 rpms and sometimes die......if I have the A/C on and let off the gas the motor drops way down and almost dies everytime....if I have the A/C on and let off the gas while turning, the motor dies everytime.....I researched it for several days and even posted it on this website under "BAD IDLE" and I was told it was a bad Idle Air Control Valve...aka IACV or IAC.

I bought a new one yesterday and I will put it on (looks easy) this Saturday then post the results....look into it and give it a try. The part cost about $75 at Advance Auto.


1992 F150 Supercab 173,000 miles 302 V8 automatic 2WD XLT

 

Fixed it.
I took the IAC off and spayed WD-40 in it since I couldn't find my card spray. I took a small flat head and scraped the carbon that was built up and then sprayed some more. Reinstalled the IAC and no problems!

 

So that worked.......good to hear. I was told my truck had too many miles to just clean the IAC and I should just get a new one.

 

Most idle probs are all IAC in Fords, its best to get a new one as the carbon always comes back too quick when you clean it. We change alot of them at the shop I work at.

 

I put the new IAC on yesterday and my idle problems stopped immediately. I am not "Mr. Fix It" but I do know a little about cars and I did it in only 20 minutes.