Replying to Topic 'Gauge Problem - Not computer'
First guess, gut reaction says a bad ground. The fact that your guages rise when put under a load makes me think this. I am guessing that the only common link between the computer, radio, gauges, and lighter plug would be the common ground for the dash. I would first check all the ground connections between the dash and the battery for tightness and corrosion. Hope this helps.
Good luck,
DKJ
1992 Supra Mariah - Red
PCM 351HO 285hp - PCM 1.23:1 Transmission
OJ XMP 4 Blade CNC 13x15.5RH
"People do weird things to boats" -Unknown