4.3l vortec won't accelerate with air filter in place

[dghahn]

I have a 2000 chevy express 1500 with a 4.3l vortec v6. This problem is driving me crazy. It started as a backfire when accelerating and quickly got worse. Now, it will start and idle fine, but if you press on the gas any more than very very gently it misses and backfires and will not accelerate.

I thought I found the problem when I unplugged the maf sensor and it ran better, but not great. I replaced the maf sensor, but it didn't fix it. I have replaced the plugs, wires, distributor cap and rotor. No help.

If I keep the maf sensor unplugged it is driveable, but if I put the air filter in, it won't accelerate at all. I have checked the fuel pressure and it consistently stays between 49 - 52psi. If it weren't fuel injected I would swear the choke is closed, is there anything equivalent to a choke in a fuel injected engine?


Thanks...Dan

[maxwedge]

Welcome to AF. The fuel prerssure is supposed to be 58-65. In the future we have a forum below for the express van

[dghahn]

Thanks. After I posted this I replaced the fuel pump, and that did the trick. I should have posted last week, your insight would have saved me a lot of time and effort. You certainly nailed it with the fuel pressure... thanks