boost gage problem HELP

[delta911]

87 turbo stock VDO Tack Boost gage combo. needle all over place on pre ignition reads .8 after start goes to .5 drive car 30 minuets shut car off restart reads .15 with power at 3500 rpm .8 4100rpm 1.plus whats my problem ? is this gage electrical or vacuum. is there a sending unit any answers I know there you guys are smart THANKS in advance.

[ObrHaus]

It is electrical and most likely the sensor itself. The contact on the sensor could be dirty or loose also, if I recall that was the issue with mine when I first got the car. Just pull your clock out and put a real boost guage in

[oilonly]

It could be your boost sensor that is installed on the intermediate intake manifold or the connection to it. It's the red colored item on this ad.

930 parts #3 F/S

[delta911]

Thanks guys