Hi scotty, my 2005 chevy suburban 4x4, with the 5.3 L V8, has an issue which shows itself when it's "hot" only; at idle and at slow speeds it bucks and the trans or differential makes clanging noises, I would say it is misfiring, and smells like lots of gas out the tail pipe, stalls, has no power, really not drivable, but no engine light or codes. None!
Only when hot does this happen and only for the last week or so. When not hot, it runs perfectly fine, also while doing this show for attention, ha, ha, ha, if you gun it and go faster, putting it under load, it seems to disappear completely and runs fine again, until you slow down then it happens again.
I've cleaned the throttle body and mass airflow sensor, air filter is clean, I changed the plugs, tried a used throttle body (that I have), checked fuel pressure (when it was cold and running fine, 58 psi) even when it's hot and having its issue fuel pressure is the same.
Plug wires have about 53k km's on them; coils have not been changed since we bought it in 2010, probably original. Pulling plug wires while running, while doing this little event does show spark on 7 coils, couldn't pull the last one on the passenger side closest to the firewall, a bracket is in the way, and I guess I was scared to.
Was thinking about throwing parts at it such as fuel pump (not changed by me before, could be original) and new wires and heat shields. Trans fluid is good but getting to the point that maybe it needs flushing soon. But I don't really think these are the culprits, thus why I'm asking you.
A couple more bits of detail, there is only an internal fuel filter on the pump, no external filter, also no external fuel regulator at the fuel rail like earlier models, must be in the pump too? Maybe? These seem odd to me compared to my astro, but that is what I've found.
Could coils be dying and showing it when they get real hot, we are currently having a heat wave here, and then maybe they stop sending enough lightning?
Camshaft sensor has also been changed, no difference.
And it has 356909 km on the odometer and is an automatic.
Thanks for any advice!
Astroratsun
Well I assume you mean hot outside and not that the engine temperature gauge for the coolant is hot. If that is so, you have some kind of electrical problem that heat affects like a problem in the main computer driver circuits or a computer sensor that gets heated up and acts wacky
