2002 Chevrolet Trailblazer EXT 4.2L Engine. It died on me the other day I got a boosts.  Later that day I got a new battery. They check the alternator and its fine. We notice the back AC was on and the truck turns off even when we turn on the ac

or heat on the front it shuts. Off what could be the problem.

 

Answer: Stalling with the A/C on at idle is usually caused by carbon build up in the throttle body. The throttle body bore and plate should be cleaned with a carbon cleaner spray. Electronic throttle systems are very common to this. Watch this how to clean throttle video. After the new battery, idle speed memory would have been lost, so it is trying to learn a new idle, but the carbon is making it difficult.


2007 Trailblazer. Engine Size : 4.6
Question : .my trailblazer will sometimes be hard to start. it cranks over several times before it will start then when i take off it surges up to 2000 to 2500 RPM's for about the first 10-20 minutes of driving it.

 

Answer: You could have a vacuum leak, restriction in the air intake or PCV system. If the check engine light is on, the computer will have information stored that can help in diagnosis. There is also an electronic throttle body on your vehicle that could be bad. That usually affects driveability and can have the symptoms you describe. Another possibility is a faulty PCM (computer) or wiring. Usually this will set the check engine light on as well or cause multiple other issues. This will probably have to be checked out at a reliable shop, as it can be a few different things. One suggestion, if you need to replace parts, it is always best to use genuine GM replacement parts.

 

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    Comments (3)

      • a.m.

        So happy I took the advice from this site. .I have a 2003trailblazer &when I turned ac on truck turned off"..I cleaned the throttle body part myself ..and it don't turn off no more truck is like new again all comments help"!..

      • Richardson

        2002 Chevy Trailblazer struggles to shift in first gear and makes a loud noise like I was revin the engine and the rpm goes buts, then it takes until I get to the next light and needs to move out again. How do I fix that?

      • Phil09

        In reply to: Richardson

        Well, i can't really understand what your problem is, but it sounds like a transmission problem and an internal engine noise.

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