High Idle Problem

[Bob S.]

I have a 1988 Blazer S-10 with a 4.3 L automatic 4x4.

I changed my spark plugs and wires the other day and it jumped the idle speed to the point it creates a problem with braking during wet weather conditions.
Anyone have advice on the best way to drop the idle? It idles to fast even after it warms up completely.

Thanks in advance for your help.

[Fractured1]

Have you checked to make sure you didn't knock a vacuum line off..look carefully at them, you mave have even cracked one, they break down from age and heat, easy to crack...good luck

[Bob S.]

Thanks could very well have had a hose Knocked off. I'll be into it tomorrow.

Thanks for the tip!

[cobra1]

sounds like the vacuum line suggested above.....

but also check that nothing is in the way of the throttle linkage, keeping the throttle from closing all the way.

[Bob S.]

You guys are the greatest! I checked it out and sure enough a little fitting had popped off and another had become a little to loose.

Even with the idle back to normal I would not mind it being a little lower. What is normally the best method of stopping down the idle?

[BlazerLT]

Do a tuneup, check your timing with the timing wire unhooked from the computer.

[terryll]

I also have a problem with a high idle. However, mine is fluctuating up and down. You can drive along and let your foot off the gas and don't slow down. I push the clutch in and the idle speed is high and then will slow down and then back up.

My local Autozone suggested a vacuum leak or a idle air speed control (I think that was it).

Any sugestions?

Thanks,
Terry

[BlazerLT]

Remove and clean your IAC valve. Idle Air Control.

They get carboned up after time. Remove it, spary it down with TB cleaner and scrub it well with an old toobrush. Rinse again with the cleaner, reinstall and remove your negative battery cable for 5 minutes to clear the computer memory so it can relearn.

Start up the truck, let it warm up for 5 minutes and then with you foot on the brake, put it in drive and stay put for two minutes so the computer can learn the idle again.