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Q: Tahoe keeps stalling, bucking, and I smell gas by the engine.

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I have a 2003 Chevy Tahoe 5.3, with a few issues going on. I was told the exhaust intake manifold bolts are broke and is causing my car to throw a bunch of codes that aren't true codes, as well as the following issues: my car "bucks" while going down the road quite violently, to the point it feels like a loss of power and my car de-accelerates. I also have an issue with it stalling in idle, or after I make a right turn (turning the steering wheel causes it to stall). I was told these are all issues caused by the intake manifold bolts being broken. I had codes throw for Mass Air Flow Sensor, Camshaft Position Sensor, Crankshaft Position Sensor, O2 Sensor, as well as one for the fuel (can't remember what it was called, all I know is I was told it causes gas to leak into the engine....which brings me to the following): I am now smelling a slight gas smell at the engine. I was told this is all a result of the intake manifold bolts being broke. I find it hard to believe. Any ideas?

My car has 174000 miles.
My car has an automatic transmission.

A: Hi and thanks for contacting YourMechanic. ...

Hi and thanks for contacting YourMechanic. With having the intake manifold bolts broken, yes you can smell gas, but the vehicle will have a vacuum leak. The O2 sensor is on for the broken bolt due to the vacuum leak. The MAF (Mass Airflow) sensor could be causing the problems for the acceleration issues.

Most Chevrolet vehicles have the wiring tied into the camshaft sensor, crankshaft sensor, and the MAF. The camshaft sensor and crankshaft sensor will come on if the timing with the camshaft and crankshaft are not correct.

Put a timing light on the vehicle and check the condition of the timing chain. If the light moves all over the place, then the timing chain needs replaced. If the light is steady, then the camshaft and crankshaft sensors need replaced.

If you need further assistance in troubleshooting the stalling and driving symptoms of your vehicle, then seek out a professional, preferably a professional from YourMechanic to help you with your vehicle.

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