Hello everyone my sons 2003 trailblazer sky rev's when he starts it up. I'm not sure what would cause this. Any ideas would be great thanks dneuhof.

 

Does it idle down later or just idles high all the time?

 

Check that your carb slide is not binding and does go all the way down and hits the idle screw OR if you have removed the slide for any reason check that you have it positioned properly on the slide cutout and inner carb slide guide. Also any air leaks around the base or head gasket,crank seals leaking,leaning out the fuel mixture,could be causing the high idle. Plus just remove the fuel line and check that flow is good also to the carb. Plus could be internal carb related problem,partially stuck float arm,etc. Several things that could be the cause. OPT