Problem accelerating

[A-2 ace]

What's up everyone, I'm been having this problem for a week now and I can't seem to figure it out? I have a 350 tbi with the nv3500 4x4 and it's been giving me problems in first and second gear when I try to accelerate off the light.. the truck will move just fine but once I start picking up rpm the truck surges down in power as if I'm down shifting.. the problem only happens in first and second gear once I shift into third and up everything is fine

 

[PlayingWithTBI]

the truck will move just fine but once I start picking up rpm the truck surges down in power as if I'm down shifting.. the problem only happens in first and second gear once I shift into third and up everything is fine

The 1st thing to check is fuel pressure at idle and under load. How old is your fuel filter? It may be partially plugged causing a drop in fuel pressure during acceleration. Once you have the fuel pressure confirmed good, put a scanner on it to see what's going on with all the other sensors including O2 feedback to see if it's going lean.

 

[A-2 ace]

I changed the fuel filter about a month ago... I will put a scanner to it today... I've also noticed my tank is keeping pressure in it, every time I open it up a bouch of pressure is released

 

[A-2 ace]

Update fuel pump was going bad causing the truck to lose fuel to the tbi system

 

[PlayingWithTBI]

Update fuel pump was going bad causing the truck to lose fuel to the tbi system

Glad you found it. Please update this thread once you replace the pump and drive it for a while.

 

[A-2 ace]

Pump has been replaced and truck is running normal again...

The gas take is still staying pressurized though? Any ideas on what could be causing this problem?

 

[PlayingWithTBI]

Any ideas on what could be causing this problem?

Check your Charcoal Canister system. Earlier GMT400s don't have a purge valve while others do. If you have a tendency to top off the tank when fueling, gas can drain down into the CC plugging it up.

 

[A-2 ace]

Check your Charcoal Canister system. Earlier GMT400s don't have a purge valve while others do. If you have a tendency to top off the tank when fueling, gas can drain down into the CC plugging it up.

OK sounds good! I'll take a look into it and update next chance I get