clean throttlebody....now high idle

88 Limited....a couple of days ago I gave the throttle body a good going over. (cleaned stepper motor, which was still pretty clean, cleaned the bore and throttle plate too) Now I have high rev on startup and then it idles back to about 1000-1100 when in park. when in drive it hangs around 800ish. any thoughts? I have a glasspack on the exhaust and k&n filter with intake pipe, thought maybe I should disconnect battery to reset ecu? would that even apply? I dont know anything about this trucks' electronic systems yet....any help is greatly appreciated

There is a TSB for modifying the Idle air controller to fix this problem. The only place I know to get the TSB is from www.alldatadiy.com. It a good site and the $25 for a year it not bad. The information you find out to fix this problem will more than pay for the subscription.

you have a leak somewhere whether it be at the IAC or the tb-intake surface. Also check that the vac lines are fully attached.

Sounds about normal for my 89 since new depending on how high your is at startup. Mine briefly goes to 1250 when cold and drops to 750-800 in drive and about 1000 in park.

Same exact thing happened to me when I cleaned my 89s TB. Senseors got wet, ttok a while to function properly again, but it eventually did.

XJguy

I checked voltages and grounds on my sensors and all checked okay...so I simply adjusted throttle stop screw back a little bit...figured maybe built up gunk had closed throttle bore and someone else might've brought idle screw out as cheapo fix. seems to be runnin beautiful now. anyone know any tips on gettin off that gas smell :wierd: (had to change dryrotted fuel line and did filter while at it, now i'm gonna be buzzed all day from the fumes comin off my hands)

Check all of the vac. hoses and make sure the gasket is good and the bolts are tight where the throttle body mounts to the intake. If it is sucking air at that spot, it will idle high. To check, spray some break kleen or WD-40 in that location and if the RPMs come up you need to tighten the bolts or replace the gasket.

If that is not the problem, take it out and run it, mabey the computer needs to "relearn" its self.