P0151 and Bucking at WOT Help!
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Teching In
Joined: Dec 2004
Posts: 18
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From: Augusta, KS
P0151 and Bucking at WOT Help! I've had this issue for a while now. It comes and goes and I've tried several different things to fix it. Here's a little about my car:
2011 CTS-V
2.55 upper pulley
ZL1 Lid
Bigger intercooler
TR7iX plugs
MSD wires
ID 850 Injectors
Flex fuel sensor
Intake
B&B Offroad pipes
B&B cat-back
Ported LS7 TB
CAI
I first noticed the issue when all I had was the 2.55, intake, and tune. Those mods had been on for a while. The car was jerky at wot acceleration, almost felt like TC kicking in but it wasn't. Never got a misfire code or anything and it only happened every once in a while. When I installed the throttle body and some other mods it started bucking, service traction control message displayed, and the check engine light started flashing. I cleaned the maf and did a tps relearn and it went away. The jerking still happened occasionally. I then put in new plugs and wires. Everything was fine for a while and then the slight jerking happened again. Finally I got a new tune thinking maybe the tune was the issue. Everything was fine again but now it's started again. This time it has been accompanied by the occasional P0151 code. I swapped O2 sensors and the code stayed with Bank 2 so I believe there is truly an issue there somewhere. I've attached a couple logs. At cruise and at idle the Bank 2 O2 output stays between 30-60mv never higher. The Bank 1 O2 output fluctuates from 30-600mv like normal. As soon as you tap the throttle it jumps right up like it should. At wot it acts like it should. Today I drove it and at wot it started bucking and the service traction control came up and check the engine started flashing. It was missing until I shut it off. When I started it again everything was fine and I did another wot test like before and it ran like normal.
This problem has persisted through 2 sets of injectors, plugs, plug wires, and tunes. I at first thought it might be an injector sticking shut at low rpm but I'm not so sure anymore. At cold start you can hear a lifter tapping on that bank but I'm not sure it's related since LS motors are known for noisy lifters. Any ideas for what to look for?
I've also verified that there are no vacuum leaks anywhere.
2011 CTS-V
2.55 upper pulley
ZL1 Lid
Bigger intercooler
TR7iX plugs
MSD wires
ID 850 Injectors
Flex fuel sensor
Intake
B&B Offroad pipes
B&B cat-back
Ported LS7 TB
CAI
I first noticed the issue when all I had was the 2.55, intake, and tune. Those mods had been on for a while. The car was jerky at wot acceleration, almost felt like TC kicking in but it wasn't. Never got a misfire code or anything and it only happened every once in a while. When I installed the throttle body and some other mods it started bucking, service traction control message displayed, and the check engine light started flashing. I cleaned the maf and did a tps relearn and it went away. The jerking still happened occasionally. I then put in new plugs and wires. Everything was fine for a while and then the slight jerking happened again. Finally I got a new tune thinking maybe the tune was the issue. Everything was fine again but now it's started again. This time it has been accompanied by the occasional P0151 code. I swapped O2 sensors and the code stayed with Bank 2 so I believe there is truly an issue there somewhere. I've attached a couple logs. At cruise and at idle the Bank 2 O2 output stays between 30-60mv never higher. The Bank 1 O2 output fluctuates from 30-600mv like normal. As soon as you tap the throttle it jumps right up like it should. At wot it acts like it should. Today I drove it and at wot it started bucking and the service traction control came up and check the engine started flashing. It was missing until I shut it off. When I started it again everything was fine and I did another wot test like before and it ran like normal.
This problem has persisted through 2 sets of injectors, plugs, plug wires, and tunes. I at first thought it might be an injector sticking shut at low rpm but I'm not so sure anymore. At cold start you can hear a lifter tapping on that bank but I'm not sure it's related since LS motors are known for noisy lifters. Any ideas for what to look for?
I've also verified that there are no vacuum leaks anywhere.
Last edited by stopltracr; Oct 4, 2015 at 07:34 PM.
