Okey dokey well....i have a 95 t100 3.4 that ivery been driving since '99. It had a motor swap at 230000 but the truck as a whole has about 440000 on it. I have done pretty much every repair that can be done and know this truck inside and out. I have tapped the knowledge in this thread anonymously for years. Now I have a ghost issue and wanted to ask directly as well as start sharing all the things I've learned about these beasts in 15 years. It only has done this twice, both in the last month. It ran fine all day, turned it off, wouldn't start after cooling down. First time it started after sitting over the weekend. No such luck this time. It cranks fine, smells like it floods (at the tail pipe) and then actually barks like it's going to start, more so when you can smell fuel. It has New MAF, TPS, coils, wires, plugs, fuel filter, air filter blah blah blah just as a matter of repairing and updating over the last few months. When i pull the plugs they are definitely wet as if not firing/flooding but i have spark. pump is 2.5 yrs old and I even have a new ecu. (Ta daaaa!!!) Checking fuel pressure tomorrow but I'm still looking for the ghost. Checked all fuses/relays. All good. Just looking for other ideas I may be overlooking. Thanks guys. This is an awesome site that I'm glad to be joining.

 

check compression. If you have fuel and spark, no compression no fire

 

I had a bad exhaust leak, cat to the pipe and the muffler was rotting off. Truck would crank and crank and crank and then finally catch. Sometimes flooring it would help and it would of course stink from fuel.Matter of fact finally truck threw a code for the rear sensor after like 10x of the crank and no start.

I replaced the cat and exhaust and also the O2 sensors. No more issues at all.