stutter stumble cough wheeze

Pretty much how my L03 feels lately for the first minute or two after I start it and it's warm. Used to only be when the engine was at full
operating temp on a restart, but it HAS been really warm here lately, and it does it at lunch time and after work when the car has been off for a few hours. First thing in the morning, runs great, no hesitation, but the last two days I'm afraid to pull out if any traffic is coming as I'm not sure if I can get across the road in time......

then a couple minutes later she jumps off the line and pulls hard (well for a 305 anyway). I know others had mentioned this in a past thread I posted but lately it's almost all the time for the first few minutes whether or not she's cold (except first start of the day).

this morning when cold it stumbled at bit. this afternoon, leaving work, I revved it up to about 2800 rpm shortly after starting and it rolled up fine in park. Started the drive and again it stuttered. Seems to only happen under load. Now if I mash it to WOT, it hesitates for much less time then takes off. Pretty much when loading it up with half to 3/4 throttle....it's starting to be annoying as hell.

Yes.....Hot restarts...... Like it's running out of gas...... When I first got my OCC it had this problem and I found the fuel pressure was set low.... I bought a kit to make it adjustable, set to specs, and the problem was fixed for a time.....Now having this issue again......I believe that it's fuel pump or wiring related, but can't see anything unusual when I have the pressure gauge hooked up.......I'm considering replacing the pump relay and maybe the pump and filter.....

Harris Performance swears by a fuel pump upgrade for the tbi's...http://tbichips.com/?page_id=548

the pisser is it used to never do this. but then again it's got about 155K on her now and it's the original FP....(it had the split hose issue around 110K). It may be telling me something, but then it picks up and runs like a champ when I go WOT.

She's my beach car, beater, daily slog to work car now, I treat her like a dirty girl lol.

I have similar issues with both of my LO5s. I have not been able to figure it out. I am about to retorque the intake manifold. Mine only does it when it has "hot soaked" for about a half hour to an hour. It acts like it is lean. After about 2-3 hours it will act like a first start of the day, and behave.

After I fixed my split hose issue, the pump lasted about a month.

If you get the 91-92 FW fuel lines, or a 93 fuel line, you can have a Schrader port for a fuel pressure gauge.

I have replaced the O2 sensor, FP regulator, fuel pump, TBI, filter, IAC, PCV valve, PCV hose, temp sender, and injectors. NO CHANGE. I am going to replace the ESC module with a used one to see if it makes a difference. The O2 sensor made a little difference for a while, but it returned to the original conditions after about 2 months. I have contemplated using a heated O2 sensor for the sake of experimentation, especially on the 91 with the headers and duals. I am putting a 454 in the 91, so I have stopped worrying about that one. both clear up in a minute after starting them.

Fred,when you have time check that link out. They offer the heated O2 sensor,and a fuel pressure port kit. The site has a whole section dedicated to the 454 Trucks. Might be worth your while...

I have them on my favorites list. The 454 is going to have a Holley MPFI system on it. It is also a Gen 6 engine.