cam081409

Hi im new to this forum, im trying to figure out whats wrong with my truck, This is only my 2nd chevy im not to familiar i usually work on imports, so if you can help that would be great.

The Problem: The truck will not run, it will start and idle, but if i press the gas it either starts to die out or completely die out, especilly if i push the gas down all the way, Also as its dying there is a loud noise somewhat like a backfire but sound like air coming from the engine

How it started: I'm not to sure how or why. The truck was running fine When parked at the gym, got back into the truck it started fine and took off fine but then suddenly it had a major loss of power and started dying when i pushed the gas pedal.

What i have tried:
Replacing the MAF sensor (still had the problem) If i unplug the Maf sensor the truck dose run better but has the same problem still.

Replaced the fuel filter

Checked Vacuum lines

There are tubes and a metal line that connects to both exhaust manifolds i checked them to make sure they weren't clogged, and also the plastic valve which looks like some sort of vacuum valve I'm not sure though, its located near the firewall on the passenger side along with what i believe to be the charcoal canister?? Noting was plugged or clogged.

Made sure the EGR valve wasn't clogged

Sprayed carb cleaner into the throttle body and there was no change in idle.

Unplugged the MAP sensor while the truck is running and it dies instantly so im assuming that is working properly.

Sprayed carb cleaner around the bottom of the Intake manifold to see if maybe there was a leak but no luck.

At this moment my SES light is not on, It dose work it come on then goes off.

I didn't do anything new to the truck i get gas at the same station every time, so i dont know what to do or where to go from here.

ANY HELP at all please...could this be a clogged catalytic converter? Or any other suggestions Please i need this fixed asap, and don't have the money to take it to the shop, and not to mention all the sensors seem to be $100+

so please help me. Thanks in advance.

ffmed6134

I would code the truck first & foremost, which engine is in your truck?
when was the last time a tune-up was done, I heard that you can drill a hole in the cats to see if you have flow or simply remove the collector from the Y and check.
or could be an evap-sensor issue that is in front of your gas-tank. There is a retrofit kit that comes w/ the new-one and you have to re-route some hoses. I would get it coded first, then go from there.

cam081409

The truck has the 294(4.8L) We did get the codes but the only time they pop up is if i unplug a sensor, if i clear them and plug the sensor back in there are no codes.

cam081409

ran the truck today until the SES light cam on, the only way i could run it was to take the MAF sensor off, but besides the MAF sensor the only other code was Idle Air Control. I dont believe its the MAF sensor because I have replaced it twice and it don't change a thing so i ordered the IAC it should be here tomorrow.

cam081409

OK sell replaced the IAC and still the same problem, I also Siphoned the gas out and put chevron supreme 91, just to see if it was maybe the gas but no luck,

If i hold the gas down and try to start the truck it wont even start. and if i don't if will start but it will idle horrible and die.

Please im trying to get this truck fixed asap so i can sell it, any help will be great.

MDTAHOE

I would check the fuel pressure first. Sounds like the pump has died. May be something else but this where to start.

mss

These trucks are known for faulty fuel senders (fuel pump), had mine replaced about 4 years ago, 1999 as well. Also while you’re at it change the fuel pressure regulator, mine used to hesitate a lot until I changed that out. The connector on top of the sender is the culprit. Did you notice your gauge acting up? Like jumping around? Mine was before it died.

99silv5.3

I am pretty much having the same issue. I have tried everything that cam081409 has done except that when i pull my MAP sensor, it continues to run. I also have replaced the fuel pump about 2 months ago with no avail. Has been ongoing for 4months now

cam081409

Well thanks for the reply's, I just sold the truck as is, i only sold it for 2500 and an in-dash DVD player, but the guy who got it got a hell of a deal, im pretty sure its something simple like the fuel pump. thanks for the help. And 99silv5.3 good luck hope you get your truck sorted out, i wish i could have kept mine but no place to work on it and need a car bad.

Mille Racer 69

Had anybody thought to change the fuel filter?
My motorcycle was doing this and I found the fuel filter to be clogged.
I replaced the Fuel Filter and /problem.
So before you put a bunch of money into it, how much is a new fuel filter? $12?