I've got a 99 5.3L with a severe hesitation on startup after sitting for 20 minutes or so. It takes a few seconds to crank and then fires, but is barely idling like its fallen on its face bad. During this hesitation there is a puff of smoke (white-ish) and smells like gas. The hesitation goes away after a few seconds and runs fine after that (no idle probs at all). Funny thing is that if I turn it off and start it back up, it fires up fine. It also seems to fire right up after sitting the night. Someone told me I may have a leaky injector that's allowing gas to pool, but I'm not sure and don't know how to check. Any help? I'm here!

 

Try putting a fuel pressure gauge on there to see if your residual holding pressure is actually bleeding off. That way you can at least somewhat narrow down the cause of your problem.

 

You might try some good gas and good injector cleaner.

 

fuel filter

 

i agree with silent. remember always KISS-(keep it simple stupid) start with the easy things. i would say find some one that has atap-efilive. maybe swap the injector. sounds dumb but check plugs and wires doubt they have any thing to do with it. then possibly pull the valve covers to check seals. or i tell you what pull the tb and stick a rag down in there and see if ther is any oil in the intake...there are so many things to check that are prety simple but there are a fiew of them and might take a while.
Ryan

 

Fuel pressure regulator. Common problem. Symptom are exactly as specified.

 

Thanks for the help, I will try and take a look at these areas this weekend to see if I can find a smoking gun. The last thing I want is to have to throw parts at this beast ($$$). Also, I've got line on some injectors (2000-2002) that are apparently rated higher than my stock 99ers. Will these drop in and run without having to tune for them???