this is on my 89 lebaron. the car was originally a TBI car and I converted it to turbo. I added a stock turbo gauge in the dash. now the wierd thing is it will read at random then stick in one place.
I know the stock gauges had vaccum lines going behind the glove box and come out the fire wall by the AC lines.
Since I had the dash apart while I was doing the Turbo harness swap, I ran the vaccum line behind the gauge cluster and out the firewall where the main harness comes out.

so is this my problem? is the vaccum line getting pinched or something?
I can manually test it with a vaccum hand pump and it works, but I can't simulate boost. I have swapped gauges with a known working gauge from another car and it did the same thing. so I know its not the guage.

what the hell is going on?