[MrTibbs]

Hi,

I had similar symptoms in my 924S (which is very similar to the early 944s). I cleaned the grounds under the dash in the footwell and the smaller of the bellhousing grounds (I found it nearly impossible to get the larger one off, so figured I'd wait until I took the intake manifold off.

My gauges were affected by the lights; the fuel gauge would say it had more fuel when the lights were on (though low warning light still came on at the right level), and the temp gauge increased a bit when lights were on.

I wired a relay system into the lights (HondadustR did a very good write up, and Daniel Stern's website tells you pretty much all you need). This made the headlights brighter but didn't stop the gauges reading differently when the lights were on.

I'd start by cleaning all the grounds (if you can get to the big one on the bellhousing great, but if not running an extra ground from engine to body might help). If this still doesn't fix it you might have to either live with it or rewire the whole car.

Good luck.

Mike