Hey guys, I really need some help. I have a ‘94 F-150
5.0 litre auto transmission. I would appreciate input
from anyone who has had this problem or has an idea
what it is. I have a low and inconsistent idle. The
truck often idles at around 400 RPM, sometimes it does
idle around 750 RPM. If I am running the AC on the
highway when I stop at the exit ramp it often stalls
due to the extra load of the air conditioning
equipment. It only stalls infrequently when not using
the air conditioner.

I did something today that gave me a nice consistent
idle at around 750-800 RPMs and I could even use the
air conditioning without stalling. I removed the
vacuum tube that enters the throttle body area from
the canister purge solenoid. Basically I think it let
a lot more air into the engine because you can really
feel the vacuum pulling the air. I know that is not
something I can continue to do because it is letting
unfiltered air into the engine but I wanted to see if
anyone knows what might need to be fixed to let more
air into the engine properly? From what I have read I
think the problem may be either the idle air control
(IAC), EGR system, or carbon in the throttle body.
Your recommendations are appreciated.
Thanks.
boatdude

 

Mine has done that twice, both times a good cleaning of the throttle body to get out the gunk fixed it. EGR eill definitely do the same thing.

 

Sounds to me like a sticking iac valve, cleaning the throttle body sometimes helps because the cleaner works its way into the valve and unsticks it, the better thing to do though would be to take it off the truck and clean it, or just replace it.

-Jon