Quote Originally Posted by mainjet View Post
Charlzm - sounds like you and I have identical issues. so maybe we can work this together and post what we find out in order to help each other.
see my post
http://www.grandprixforums.net/sound...you-53934.html

Also, my HUD will go out by itself and then come back on...

BTW does your performance shift work at this point?

Appearently the trip calculator does a self test and if it does not get the serial data that it wants within 10 seconds it flashes zeros. Here is a blurb from alldata
"The trip calculator performs an error detection when a serial data stream is not present for 10 seconds. If the trip calculator is not able to calculate a value, due to any missing data, the display shows a flashing 0 when the mode is selected. The trip calculator updates the display with the correct information for each mode that is selected within a given time frame."

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Interesting...

My HUD has gotten very dim but still functions without issue. I can't see it in daylight hardly at all any more, but I still see it at night.

Performance shift is fine. As you may know, the indicator light for P.S. mode in 98's is on the dash (not the DIC) and it still functions properly.

Trip Calculator? I don't have one of those. The DIC in my 98 shows MPG, fuel used, oil life and range. For a brief few seconds at startup (before the zeroes take over, the info will display on the DIC correctly. It doesn't seem to be keeping up with the fuel-based items but the oil life is still ticking down at what seems like an appropriate rate.

I'm wondering if the fuel sender mentioned by BillBoost might be the culprit. Still, that wouldn't explain the TCS and ABS lights staying on steady and once in a while flashing. When they flash, the DIC starts working again.

I may just bend over and take the car to the GM dealer nearby for diagnosis. Will let you know what I find out if I do.