99 gmc,,, problem......

im having a problem with getting my truck running... its new body style with 5.3L it starts and runs for like 5 seconds and shuts off.. the battery is good, the fuse's are good, my fuel pump is working i have pressure!! my ignition is also good.. but i was just wondering if any one else has had this problem and have sum advice 4 me!?!?! if so or not thanks for takin the time to read this...

is the security light going off? the yellow lock on the dash?

just because there is fuel getting there, doesnt mean its enough, should be something like 55lbs not sure exactly maybe someone can chime in.

yea it is

but im pretty sure that light has gone off before when i started it

Did you have the truck apart recently or did it just start doin' it?

is your service engine light on?

Do you have any codes?
You would need them to get a better idea where to look.

Also I use LS1tech.com Search the forum. there is lots of help there for our type of engines
your 5.3 is a Generation III small block. Just like the LS1. So you could start your search there.

Good luck.

I have unplugged my battery a few times in the past and when I did when I first start it up, it last for about 5 seconds like you say but I take the keys out and then try again and it starts right up. I believe I have had this on the forums before and someone told me to have my ecu checked out. Maybe reprogrammed.

no i have not had it apart lately it just did it monday and i havnt drivin it since... there is 1 code on there that wont go away but it is because i took my smog pump out like 6 months ago but that is it... i have drivin it everyday since then thanks for the help guys!!

i had a 99 s10 did the same thing it sat for like a month and had it sold went out to start it for the guy and it did the same thing had it towed to the shop and the stock security was fed up they just need to flash the ecu