stumble on hard accell

[donj303]

My GTP stumbles on hard accell under boost. Runs good all other times. Checked values with a Snap on modis and showed 99 % boost all times. Checked and had battery voltage at boost solenoid, though never had vacuum out of it. Check boot control val. Checked and boost control valve seems to be wide open unless under accell. Have good manifold vacuum at one side of valve, but added vacuum to other side ( with vacuum pump ) would not hold. Took belt off supercharger and runs good, of course loss of power. Do either of these valve or solenoid seem to be common, or am I barking up the wrong tree. appreciate any help. Thanks, Don:

 

[EyesofThunder]

Any reason you are chasing the boost control valve?

Just a thought, when under boost the ignition system must be in tip top shape. The boost will attempt to put out the spark if it is weak, I have seen way too many 3800's with rusty terminals under the plug wire boots. Take a look, ensure everything is good.

I have a momentary power loss when I get on it that I believe is Torque Management related, I don't care for it, but it is there. I'll address it one of these days again.

My GTP stumbles on hard accell under boost. Runs good all other times. Checked values with a Snap on modis and showed 99 % boost all times. Checked and had battery voltage at boost solenoid, though never had vacuum out of it. Check boot control val. Checked and boost control valve seems to be wide open unless under accell. Have good manifold vacuum at one side of valve, but added vacuum to other side ( with vacuum pump ) would not hold. Took belt off supercharger and runs good, of course loss of power. Do either of these valve or solenoid seem to be common, or am I barking up the wrong tree. appreciate any help. Thanks, Don:

 

[machinegun]

I think your issue has nothing to do with the boost bypass system.

I would look first at plugs wires and coils.

These items in not perfect condition will cause most cases that you describe. I can not mention the number of times people come with a surging / stumbling issue and nothing more than new plugs and wires has resolved the issue. Check them out and let us know.

 

[garyk1970]

spark plugs gaped too big....or plugs' wear an issue?