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GMTechBernard, Shop Foreman - GM World Class Tech
Category: Chevy
Satisfied Customers: 2158
Experience:  GM
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chevy trailblazer: running rough at stop lights i..fuel filter..ran ok

Resolved Question:

I have a 03 chevy trailblazer it was running rough at stop lights i could see on the tac and feel a slight miss so i changed the fuel filter i seamed to run better i did not notice the miss but when i climbed a hill it misses horrible i could not go over 40 once i got up the hill i ran ok any ideas
Submitted: 9 years ago.
Category: Chevy
Expert:  GMTechBernard replied 9 years ago.

Three things come to mind:

1) throttle body. It won't cause the low power/miss going up the hill, but when carboned up, will cause funky idle. Some standard carb cleaner and a rag will clean that. Soak the rag with the cleaner and use a screwdriver to hold the throttle open and clean away.

2) One source for the miss could be a bad coil/spark plug. Water can collect down inside the spark plug hole and damage the plug and/or ignition coil. Usually, you can remove them and spot any water issues (will appear rusty or corroded).

3) The last thing, is the possibility of a plugged catalytic converter. That will cause a miss or loss of power, especially climbing up hills. If it is indeed a converter, its covered for 8 years, 80,000 miles under factory emissions warranty.


Hope this helps.

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