Hello,
I am new to the ford world, and bought a 98 FCV with 150K runs excellent the intake manifold has been changed since the original one leaks. 2 days coming home from work I stopped at the red light and all the sudden the engine revs high as im in gear holding the brake down. the motor stays revved up about 2 to 3 K RPMS the car ran perfect before hand and all the sudden it just startted idling high please help

Thank You

 

First thing to look for is if anything may be causing the linkage to hang. Also look inside the bore of the throttle body to see if there is a lot of carbon built up. It is possible the IAC (Idle Air Control)is hanging open causing the high idle.

 

Hello,
I took it to the shop yesterday, they called me back and first said it was the IAC and then 20 mion later call me again and said they found a leak on the manifold. so i paid 90 bucks to find the problem. now i am gonna take the manifold off and see if its craked or if its the gasket. they were not sure either until they pulled it off. if its the manifold im looking for a high performace one not a stock plastic one.... can anyone help me give me links with aftermarket manifold for the that motor>>>

thank you

 

it was the AIC after all I took it off and hit it with the hammer and put it back and now its working

 

Hah....the good ol, hammer trick, that is good for the check and see but I might have got in there and cleaned and lubed the screw drive for it...(assumes it has that kind of actuator...my GM did) But hey if it is working then all good.

 

Hi, I once had a similar problem with mine both a Crown Vic and other fords and it was the IAC valve. However when I attempted to clean it out, it made the problem much worse! Those things are not really meant to be hammered upon or cleaned when sticking. Your safest bet for long term idle happiness and to prevent an unexpected dangerous situation while driving is to invest roughly$80.00 for a new one. Try google searching "Genuine Ford Parts" for good prices on a Motorcraft IAC, or your local Ford dealership; stay away from aftermarket brands on these.
I also bet that your problem was partially due to the manifold vacum leak. You can easily check for vacum leaks by spraying a little throttle body cleaner around various areas of the engine and hoses etc., while it is running and listening for an rpm change after each squirt. If no change then no leak. I'll bet that when the manifold leak is taken care of and the IAC valve is replaced your Vic will idle perfectly. Please note that I have a high idle problem thread posted in this forum but it is a completely different type of issue.
Hope this helps,

Jayrome