This is a not-uncommon problem and 99 times out of 100 is nothing more than the two multi-pin electrical connectors behind the instrument cluster not making a good solid electrical contact with each other.
You can remove the instrument cluster in 5-10 minutes, it's easier to remove than it looks (you only need a phillips head screwdriver), and then you'll see the two multi-pin connectors behind it. The male pins need to make better/more reliable contact with the female pins and that's fairly easily taken care of. With a pair of needle nose pliers, gently (!) squeeze each male pin so it is just barely flattened a tad. Not flat, just a bit oval-shaped. That way, they'll have a tighter fit when it's all put back togetehr again and your intermittent instrument cluster should be a thing of the past.
I took care of mine like that 12 or so years ago and it's been fine ever since.