05 Tahoe 5.3 stalls under hard acceleration

[Nate_87]

I have a 2005 Tahoe Z71 with a 5.3. 210,000 miles It has showed the following codes foP0171, P0174, P0332, P0446 for the last month. I’ve owned it since August.


First problem. When trying to start after sitting for a while, (30 mins to an hour or so) the first crank it will crank for about 10-15 seconds before hitting but if I let off the key and try again it usually starts quick. The lot I bought it from said they replaced the fuel pump already. It acts like it’s losing its prime.


Second problem. Yesterday I was driving with the cruise set and while going up a steep grade it went to downshift and stalled. Kinda acted like it wasn’t getting fuel. Once I came to a stop and popped the hood, I noticed a rough idle and would almost die when trying to pull out in drive and reverse. Also there was a sound coming from under the hood when the gas was pushed. (Kinda sounds like a backfire coming through the airbox). After sitting for a couple mins I fired it up again and everything was normal. But any time I try to kick it down and accelerate hard it stalls and won’t take fuel.


I have cleaned the MAF sensor and the throttle body looks clean. I have checked for vacuum leaks and sprayed around the intake gasket to see if there are any changes in idle with no results.


Any ideals of what could be causing this. Any advice is appreciated. Thanks in advance

 

[S33k3r]

Have you checked the fuel filter?

 

[Nate_87]

Have you checked the fuel filter?

That’s what I was thinking. But after doing some research I believe it is in the tank on this year.

 

[swathdiver]

The Bank 2 knock sensor is bad. But the lean conditions on both banks (171, 174) are probably caused by code P0446, which is an evaporative emissions vent systems performance code.

DIAGNOSTIC AIDS
 An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the
EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system will also
cause a poor fuel fill condition.
 An EVAP canister filter that is restricted can cause this DTC to set.

A Tech2 can make short work of finding the culprit but other tools may also be required.

 

[Nate_87]

The Bank 2 knock sensor is bad. But the lean conditions on both banks (171, 174) are probably caused by code P0446, which is an evaporative emissions vent systems performance code.

DIAGNOSTIC AIDS
 An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the
EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system will also
cause a poor fuel fill condition.
 An EVAP canister filter that is restricted can cause this DTC to set.

A Tech2 can make short work of finding the culprit but other tools may also be required.

Would the knock sensor cause the lack of power when accelerating ?

 

[swathdiver]

I don't know for sure but reckon that that and the lean condition would cause the computer to try and protect the engine.