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Q: Engine revving, backfiring, cannot accelerate past 40 mph - 1990 Chevrolet G30

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Whenever I rev the engine, I notice backfiring. I think it's coming from the carburetor area. It makes a popping noise. I'm unable to accelerate past 40 mph. The engine never stops revving and cannot idle down. I had the fuel filter replaced. The carburetor hose to the distributor cap is good. What might be the problem?

A: The poor performance and backfiring through...

The poor performance and backfiring through the intake you mention are signs of a "lean" condition - not enough fuel for the amount of air flowing through the engine. You may have a vacuum leak or Idle Air Control valve problem. If you find you are still having issues with this, a professional expert from YourMechanic can come to your home, and diagnose the backfiring issue and make any necessary repairs.

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