Matteaton

Having issues with my 2000 Chevy Silverado 1500, runs very rough at an idle when cold. It will almost die then Rev way up to 2000 rpm all on its own. tried plugs and wires and replaced mass air flow. If I unplug the mass air it actually runs fine other than idles to high. But it always sounds like I have a huge cam in it at an idle and seems to not have all the power it used to. Can't seem to figure out what the deal is. Its not throwing any codes either

Jared Phillips

I would check the intake manifold gaskets. Probably need to be replaced. When they go bad, they leak air when cold. After the engine warms up, they seal and don't leak, and it runs smoothly.

Matteaton

Just replaced my intake gaskets and now it runs great at an idle but misses down the road. Completely backwards from what it was doing any suggestions

Tyler Clark

SkipperSkeet

My truck has about the same amount of miles (150K). It would have trouble starting in the cold (especially mornings) and then would be misfiring until I had driven it for about 15 minutes. Later in the day it wouldn't ever misfire once it was a little warmer.
I replaced the spark plugs, ignition coils, and ignition wires (AcDelco). It helped a little bit but the plugs were also old anyways. After doing some research and asking some mechanics I dug in and replaced the manifold intake gasket. The next morning was about 19º and she started right up without issues.
Takes a little bit of time but there are a couple really helpful youtube videos that can be very helpful.

AvalancheTX

Try replacing Knock Sensor: CODE P0332, P0327. Part# 917-033. YouTube for videos. I changed mine and engine ran smooth and no more chocking/knocking.