high idle

[momentum]

Hello everyone, I just got on to this forum and I'm glad to see something like this exists on the web!

I have a '95 c1500, 350, 5spd.
When I start my truck in the morning or if it has been sitting a while (e.g. all day at work), it idles at approx. 2000rpm or just under and takes about 3-5 minutes to get to a healthy rpm idle. My friends say that it is normal, but I question their knowledge. I have replaced the idle air control valve and the problem still persists.
What else can I do?

[95silverado]

That's not normal. I just started my 95 up (cold start) and it idled at 1200 for about 15 seconds, then dropped to around 950 for about 2 minutes, then dropped to about 600. Check for a vacum leak. The line from the throttle body to the pvc valve split on my truck and caused a high idle. The diaphram in the power brake booster can cause high idle also. hope this helps.

[momentum]

Thanks, but I checked all those things and I still have to kick out the high reving!!??!! Do you think having an aftermarket air intake has anything to do with it?

[95silverado]

I don't think the aftermarket air intake is the problem. You shouldn't have to touch the gas pedal to get the idle to come down. The idle speed is controlled by the idle air control valve, and you have already replaced that. What does the idle speed come down to after the engine warms up? You could have binding throttle plates, or an air leak under the throttle body.

[momentum]

Originally Posted by 95silverado

I don't think the aftermarket air intake is the problem. You shouldn't have to touch the gas pedal to get the idle to come down. The idle speed is controlled by the idle air control valve, and you have already replaced that. What does the idle speed come down to after the engine warms up? You could have binding throttle plates, or an air leak under the throttle body.

The idle speed comes down to 1000rpm after it warms up. I will check and clean the throttle plates tonight and see if that helps. Thanks.