07 Chevy tahoe Engine misfire trouble

[Tahoeloverman]

On my 2007 Chevy Tahoe I’ve been getting a random misfire P300 code on cylinder 4 sometimes it will randomly throw a misfire on two and three, but this has been happening for a while now. I have changed the spark plugs, coil packs, coil pack wires, got a new ECU change both upstream and downstream O2 sensors, and now I am lost. Will love advice if you guys have any.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

 

[OtterHusko11]

Not super experienced in these trucks but a misifire could also be cause by lack of compression or lack of fuel. I would start with checking your injector for Cylinder #4, one easy way if its accessible is using a long screw driver as a stethoscope listen for clicking use another cylinder thats not mis firing as a reference, it may also be clogged or plugged up not allowing enough fuel. After you run for a while pull the spark plug and take a look at the end that will tell you alot of whats going on.