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Q: Sometimes my car has a rough idle and even stalls - 2004 Chevrolet Tahoe

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I've been having a rough idle and sometimes even stalling. RPMs drop, volts drop, and oil pressure gauge drops. No problems going down the road. Also if I pour a can of seafoam in the tank at every fill up in won't have any issues. Things that I've done already: 1. Had throttle body and injectors cleaned 3k miles ago 2. Changed to synthetic oil 3. Cleaned mass air flow sensor 4. New air filter 5. New battery 6. Alternator is less than a year I have owned this Tahoe for almost 5 months. When I had the throttle body cleaned the shop said it looked like it had never been cleaned. Running seafoam in the tank will have it running smoothly, but as soon as I do not add it the problem comes right back. Not sure if the throttle body and injectors need to be cleaned again or if it's something else.

My car has 124000 miles.
My car has an automatic transmission.

A: Hello. From my experience with this engine,...

Hello. From my experience with this engine, the issue is usually due to the fact that the throttle body plate is worn out in the bore, or, more commonly, it is caused by an issue with the intake manifold gasket leaking. I always scan for codes first and check the fuel trim readings which would tell me if this is an air leak issue. Then I check for leaks around the intake gasket. It can also be a failure in the MAF, but that is not as common.

If you want to have this low idle fixed, consider having a certified mechanic, such as one from YourMechanic, come to your home or office to diagnose why the car is idling rough.

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