I have cleaned the throttle plate on a 2007 GMC Sierra. After cleaning it the RPM will reach 2500 by itself. When the truck is put into gear the RPM will decrease to normal. after putting it in park and hardly touching the throttle the RPM will climb back up to 2500 RPM before I shut the truck off. Any clues would be helpful.

SOURCE: 2007 gmc sierra 2500 IAT sensor

Well, the IAT (Intake Air Temperature) sensor is located on the air intake duct between the filter and the throttle body (Assuming you have the 6L motor). The wires are easily visible at the plug that connects the sensor to the wiring harness. That's the easiest place to access them.

SOURCE: 1999 GMC Sierra 2500 Won't Start

Try loosening the terminals and turning them a bit after spraying them with crc dont take them right off or you might loose the radio code also check the other ends eg earth and starter and do the same if the battery connections don't fix it hope that helps

SOURCE: 93 gmc sierra heater not working

THERMOSTAT REPLACE IF NOT SEE IF HOSES ARE CLOGGED SHOT OF AIR COULD HELP OR DISSCONNECT BATTERY CABLE 10-15 MIN CONNECT BACK TRY HEATER

Harvey N Tawatao

• 3854 Answers
• Posted on Apr 13, 2009

SOURCE: how to adjust parking brake on a GMC Sierra 2500

The adjuster is just like on a car with drum brakes. It can be adjusted with the wheels still on the truck, but if yours is out enough that it doesn't work, an inspection is warranted. Axle seal failure is common and will soak the shoes.

Jacked both rear wheels off ground, and while slowly spinning wheel, tighten the star-wheel adjuster until you just hear and feel brake drums rubbing, then loosened slightly.
There's a plastic dust cover about 1/4" X 1" that you remove, and use a drum brake adjuster tool.

The driverside access hole is below axle, easily accessable. To tighten driver side rear parking brake, turn star-wheel adjuster down.


The passengerside access hole is found above axle, and difficult to see. Removed pass side wheel and used an inspection mirror.
To tighten passenger side rear parking brake, turn star-wheel adjuster up.

Good luck and hope this helps. Oh and the other thing to is that if you do smell axle fluid around the wheels and see oil leaking from the drum area. Then you have a axle wheel seal and or bearing gone bad too.

SOURCE: 1989 gmc sierra 2500 problems

I just had the same problem. My speedometer was jumping up and down randomly, then would die completely...followed by all my other instruments. I thought i had a bad ground and spent hours looking. Soon followed a shifting problem where my it was not auto shifting. I had to manually change from 2-3, with no first gear. I immediately thought ground problem on the tranny. No luck again. Took it to have the codes read, which pointed to all shift solenoids, but i knew that could not be it. I was still set on a bad ground.

Took it to a transmission specialist to see if he had heard of the problem. He took a look and said it was the ignition switch. I though, how the hell does that have anything to do with...instruments....shifting...some many problems. Sure enough, i replaced and it runs like a champ. Hope this helps.

Chad