Stock boost guage jumping

[cattig]

I was wondering what controls the stock boost gauge. It seems to be jumping around erratically. I have an after market gauge install also and the boost on the after market gauge drops when the factory gauge starts to fluctuate. Is the factory gauge run off the MAP sensor or something else?

The truck also seems to run erratically when it is cold. I was assuming this was due to the truck running in open loop mode due to it being cold. I was wondering if the two are somehow connected.

 

[nick041881]

most of the times when the truck stumbles it is ignition related, so i would go through you plugs, wires, cap....and see if that helps. the fluctuation in the boost gauge could be a vacuum leak. i would also go through and check all you lines and connections.

 

[cattig]

I was watching the boost gauge again today and the autometer was holding steady and the factory gauge was jumping around. My question I guess is the factory gauge run off of the MAP sensor and is this a sign the MAP is going bad.

The plugs (CR42TS), cap and rotor (CONRAD RED), were changed 4000 miles ago. The plug wires were changed 12000-15000 miles ago to KB red hots. I Also checked the vacuum system 4000 miles ago and found no problems.

 

[Tooky]

Yes I beleive the stock boost gauge runs off the MAP sensor. If you think your MAP is bad or erratic, I would check it on a scan tool to verify.

 

[SY756]

The stock boost gauge does take it's readings from the MAP. If you have a scan tool of some sort check the vac and boost readings on it. I think if your map was bad you would be experiencing some driveablity issues. You could have a bad contact in the gauge cluster causing the jumping gauge.