[PikesPeakMtnMan]

I have a 1995 GMC 1500, 5.7L, auto, 4x4.

A lot of the times I start my truck the speedo and tach and the little light showing which gear I'm in (P, R, D, etc) don't work. If I shift into reverse it shifts fine but it "clunks" into Drive. When I drive, the truck accelerates like the parking brake is on (seemingly more RPMs than necessary and very little speed to show for it) and the shift points seem off (though the engine doesn't rev noticably or anything). Occasionally, while I'm driving everything "magically" starts working normally again.

All the other gauges and lights work normally and not only are all gauges within normal ranges, there are no odd sounds, smells, leaks, etc.

I haven't noticed any correlation between cold vs. warm engine, ambient temp, etc, etc.

Most of the time when I start my truck and notice the problem I will... A) not drive...B) turn it off and restart it until the problem "goes away"...C) drive anyway (because I have to get back to work or some other "urgent" circumstance) and hope for the best.

This is a new problem for my truck. However I have some problems that I haven't fixed yet because they are mostly nuisances and not major issues. I doubt any of this caused my current problem but I'll explain just on the off chance it is related.

I have what's been explained to me as a "short on the ground side of the circuit" somewhere deep in the electical bowels of my truck.

--My 4-way flashers will drain the battery in about 5 minutes if the engine is off...

--My interior dome light doesn't work via the doors, only with the manual switch, my cargo light doesn't come on unless the dome light is also on. (I put in a LED hi-mount brake light and realized the cargo light worked just as it should but the brake light would flash and quickly fade out when the brakes were on.)...

--I notice LOTS of voltage draw with multiple accesories going (radio, headlights, fan blower on HIGH, windshield wipers all at once)...if I keep my blower motor on anything but HIGH then I'm okay.

So far everyone I've talked to about my tach/speedo problem has been stumped so hopefully someone here can help me.