I'd prob start with cleaning throttle body and take a look at your spark plugs. If one isn't like the other that may narrow down the problem.

Years ago I had a hard hesitation then it would let go and be normal. Ended up being a clogged catalytic converter.


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I changed my plugs and cleaned my throttle body not very long ago. I re-checked them and they still look good. I haven't tried cleaning my MAF sensor yet and it's throwing a code for the EVAP
solenoid control circuit.

 

Fuel Filter or something fuel related. Opening the throttle gives you air. Fuel then comes in after. So if it bogs low rpm to mid its probably lean. Change your fuel filter even if it looks ok. or you might have a blockage in your fuel rail. Run a FULL fuel system cleaner (BG 44k or Lucas full system cleaner). Really sounds like a fuel delivery problem.

 

The fuel filter is part of the fuel pump in the fuel tank. You can’t just change the fuel filter in these trucks like you can other trucks/vehicles. Found that out the hard way after searching high and low up under mine for one for like 30-45 minutes one day. You gotta replace the entire pump or nothing at all.

 

Change out the evap solenoid should be a how to or bad gas cap

 

http://www.355nation.net/forum/i4-i5-engine-drivetrain/57479-evap-emission-obd-code.html

 

I ran the fuel system cleaner through it already with no difference. And it's not the solenoid on the engine it's the vent solenoid mounted under the truck. So I'll probably try to replace that. And also I've noticed my gas gauge has been malfunctioning because it will say I'm empty but when I fill up it only takes half a tank or so sometimes. But not always.

 

Fuel filter is in the tank, which is why it was moved there on the 06 on up trucks and the chances of it clogging are very slim.(which is why GM moved it there, it also makes replacement a bitch, haha) Instead, I'd look harder at your MAP sensor (near the top of the engine, after the resonator and throttlebody to your right) from what you're describing, get a OBDII code reader or get some one with one at a AutoZone to check to see if you have any pending codes on the truck related to it. Oh and definitely get some CRC Mass Air Flow Cleaner on that MAF sensor, the sensors on the engine on this truck are VERY touchy and if one is failing, it will make your truck run like crap and give you utter hell until you replace it. Ask me how I know... *sigh*

Ahhh yea, the Evap canister replacement is pretty simple and easy, (it's right under the spare tire) and the canister (a cheaper H2 version part without the vinyl tubing will work too) to fix that as well.


Hope this helps, good luck!

 

just turn the entire evap bs off in a tune.

 

what was the DTC for evap?