My girlfriend has a 2000 RCSB 4.8L 5 speed silverado with 73,000 miles on it and it has been having trouble with starting. It turns over fast, plenty of times until it finally sputters to life. When it does fire up it boggs real low like its going to die and barely keeps itself running. It runs fine once your driving it. The air filter is an almost new K+N and i just recently replaced the spark plugs and fuel filter to try and cure the problem but nothing really changed. I used the ac delco plugs that it calls for at about 5.00 each. I have no clue what else it could be since it seems to run fine when your driving it. What do you huys think it could be??? Anyone else have this problem???

 

I bet its the fuel pump, these go bad often on these trucks. Mine did. also you can check the fuel regulator at the rail, and vaccum tube to regulator. doesn't sound like a spark plug or air filter problem like you mentioned.

 

You may also need to clean your maf. There is a good chance of it being the pump though

 

I would check your fuel pressure regulator. It is on your fuel rail, take off the vaccum line and check to see if there is any gasoline in the actual line on inside the reg. I fyou find some then replace it. Good luck!!

 

I would say pump, my brother has a 01 4.8 the symptoms sound the same.

 

yup, my 01 4.8 did the same exact thing. sometimes it would die, but it was off an on.. never bothered me that much just let it go

 

 

same here.

 

Test the fuel pressure with a gauge before replacing anything. If it checks out fine, Carefully remove the IAC valve and check for excessive sooty buildup in the passages. Use throttlebody cleaner if needed.

 

After checking for the presence of fuel in the hose to the fp reg, I'd also check the IAC valve. Try cleaning the throttle body and all of it's passages real good. Several companies make spray cans of throttle body/ induction system cleaner that should work. (I use BG myself)

edit: deathmobilesuburban, we were thinking the same thing