High idle

[wards]

I have a 93 L that is doing the same thing yours was.

What did you do to resolve it?

1. High idle 1500 RPM
2. Slow RPM drop between shifts
3. Occasional sporadic idle goes back and forth from 1500 to 1700 RPM four of five times in a matter of 15 sec then settles back to 1500 RPM ( The first time I noticed this is was when the cooling fan came on, fan sounds like it may be going bad.
4. Slight let up of gas pedal feels like you took foot completely off gas, but then resumes normally when pedal is slightly depressed again.

[wards]

Bump

[Huli]

Re: High idle

Bump!!!

93 L - high idle only when warmed up fully. Rest of the time it is fine. Adjusted dashpot, asdjusted TPS, checked for vac leaks.

[Huli]

Fixed mine, I think.

Had to back down the throttle stop to just barely touching.
Then I reset the TPS, but instead of putting the feeler gauges at the dashpot, I put them in the throttle stop bolt (made more sense).
Opened the idle screw on the throttle body 3 turns, and cranked the engine.
Allowed it to stabilize.
Turned in the idle screw till it sounded good (do not have a hand tach)

Before, the idle screw was all the way in, revs were WAY too high. Now, engine stumbles bad if I even get close to turning it in all the way. Test driving tomorrow and will see what happens. Going to take it to O'riley's and have them hook a hand tach to it, and set it right!

[spoman]

Could be a stuck choke plate?

I'm kind of having a similar problem. Another possibility is the Fast Idle Cam Breaker (FICB) is malfunctioning. I had a similar problem with a previous vehicle. I ended up solving it and a couple of other problems be rebuilding the throttle body.

[Huli]

Mine was the throttle stop was not properly set. Well, will see tomorrow when I drive for more than 5 minutes... lol

Forgot to mention, that I had to adjust the throttle cable too. When I adjusted the stop, the cable came tight. Loosened it 1/4 inch of threads! That is a huge amount in air mass going past the butterfly valve.