Chevy Silverado Cutting Out Looses Power

Ive got a issue with my 2005 Chevy Silverado 2500. It’s got the 6.0L engine. It will run fine for a few minutes then all of a sudden it starts cutting out, looses all power, and acts like it wants to stall. I have replaced the exhaust manifold because there was a crack and I thought maybe that would cause power loss.

I put new plugs and wires on it. I also put on a new mass airflow sensor (MAF). Nothing seems to help and I am at a loss on what could be wrong with my truck.

ANSWER: If the check engine light is on, the first thing you need to do is check for any stored trouble codes. You probably have P0300 misfire codes. That could be caused by sticking fuel injectors, low fuel pressure or an ignition problem like a coil going bad. If the engine light is flashing, that means the misfire is bad enough to cause catalytic converter damage.

If not, then you will need to get a fuel pressure gauge and check the fuel pressure when the engine is starting to lose power. Compare it to when the engine is running good. If the pressure is too low, the fuel pump may be going out. Normal pressure is about 60 PSI.

If the problem only happens when accelerating, you could have a plugged catalytic converter. These will usually give an oxygen sensor code or catalyst efficiency code. This is pretty common on the 6.0L engine in the Chevy and GMC trucks. You would also feel a hesitation on hard acceleration.

This could also be the original problem of the manifold cranked. Backpressure can cause this.

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