If it has GM gauges there was a problem with them through those years.
I have a 2004 Chevy Silverado PU that I bought new and have babied now with only 107,000 miles on it.
My gauges started acting up and I found that they use "Step Motors" to read the information. There were defective motors during that era.
I bought a new set of upgraded motors on ebay for $16. and had to remove the dash and solder them in. (instructions on u-tube)
Not sure if this is your problem but this info might help someone else.
