Well I know for a fact my truck used to prime it's a very loud easy noise now nothing. Bad gas I doubt it, the truck drove just fine an hour earlier. Usually you hear of fuel pumps dying slowly, if it is the pump I will be surprised it just died like that.

Gotta ask one more time, is there any reason why the tune for 3.42s could have anything to do with this?? It's just so weird that I get gears and then 4 hours later this happens....but it makes no sense to have any relationship to the problem

 

I've heard of and worked on vehicles that the pumps have gone out with no warning, I wouldn't be surprised if it's the pump.

 

when my battery was crapping out it would die alot at red lights, but your problem definately sounds like a fuel pump

 

HA! Exact same thing happened to me. Got rearended and bust a leak on my long tubes. a month later was coming down the hill from taft and my pump died while i was going 70mph. Had to cruise all the way down. Long tow home that night

 

Yeah, I'm just waiting now on the fuel pump I got from a member here. Shipping slow as molasses. I had the truck towed and it's sitting on the side of the street and I'm nervous a bit nervous since it's a high crime area. Normally I park in a gated lot.

 

I've had pumps go out like this before too. One day it wouldn't even start, the next day it would run for 10 minutes then die. It isn't always a linear progression. I don't see how the tune could effect anything other than your speedo or shift points maybe. I think the pump still functions just enough to deliver a little pressure at idle but just can't keep up under a load.

 

sounds like your fuel pump. it also sounds like what my truck would do in limp mode.

 

When your truck is warm, how many pounds of oil pressure does your truck have at idle? Mine is 35lbs with 102K miles.

 

off the stock gauges mine idles at 45-50.
cruises on the highway at 65-70
and pegs 80 when i floor it

 

My engine is a 2002 LQ9. At cold start it makes 55-60lbs. When it's warm it's about 45. A WOT is makes roughly 75psi.

In 2004 i believe GM put stronger oil pumps on the engines that will peg out the gauge. Most of the earlier engines make 70psi at wot