P0304

[codydellinger]

Hey all,

I have searched the forums and apologize if I missed information.

I have a 2009 Tahoe 5.3 that has 186k miles. It has ran great, has newer spark plugs and wires. I tow every other weekend with it, nothing crazy. Yesterday, not far from home, while towing roughly 2000lb, I was going uphill and got the flashing check engine light with the stabilitrak light. I immediately pulled over and turned the engine off. When I started it back up to head home, it started misfiring, shaking and I heard what sounded like a lifter tick. This only lasted a few seconds and went away, and it drove fine back to the house.

Today, I replaced the spark plug, wire and coil pack on cylinder 4. I did each individually and drove it each time. The car does not idle bad at all, but throws the code as soon as I reach the same distance from my house as yesterday. Today, at no point did I hear a lifter tick. It did however shake and carry on while the light was flashing.

Any advice would help... Im hoping for maybe an injector or electrical issue, just due to the intermitting circumstances and how it acts up at the same point each drive.

 

[j91z28d1]

check for spark and fuel on cylinder 4?

 

[solli5pack]

Gonna need scanner that shows live data.

 

[rdezs]

Live data would be immensely useful.

If you have ruled out spark and fuel delivery, next up is a compression and leak down test. You can just swap a fuel injector and see if the problem stays at cylinder number four or moves.

My gut instinct from the symptoms you describe suggests you might have a lifter that's getting ready to go.

 

[OR VietVet]

Welcome to the forum from Oregon.

Yes, get a live data scanner and see what is going on. They are not that expensive. I like the Foxwell NT301 for about $75.

I agree with @rdezs and think it could be a lifter but I would do a compression test. Make sure all 8 plugs are removed when the compression test is done and especially do the test on #2 and #6 and compare all 3 cylinders.