ok, so the last couple of days, my truck has been running funny. under light acceleration it was fine, but when you punched it, it would backfire through the exhaust. i checked the timing and it was ok. so im at a light yesterday, idling rough, i went to take off and it hesitated. it was around 200 rpms deciding whether to go or die, and about that time it started "dieseling". no start after that. i waited for a tow truck, and right before he got there i decided to turn it over and see what it does. It was the loudest freaking backfire through the exhaust i have every heard. got it towed back, and going to work on it today. weve got a poker run here tommorrow

the truck is a 1993 chevy k3500 with a 454.

help

damn, i wish i would have checked last night. i told someone and they assured me it jumped time. so i ripped everything down and the timing chain feels tight. i cant get the cover off, do you have to pull the oil pan to get the timing cover removed? I might as well change the chain while im there. how hard is the ignition module to change. just unbolt and bolt a new one up?

Loosen the oil pan and drop it down in the front to get the timing cover over the lip on the pan.

Yep, I would put money on the ignition module. Bolt the front of it back up, and go get the module. I have never heard of a motor jumping time. Its a little piece that is in the shape of an apple slice with squared off corners. It sits directly under the distributor cap. 10 minute install.

Oh yeah, label your wires.