Same thing happens to me bro. I'm not sure why, I'm pretty sure it's a common problem... I'll keep an eye on your thread... thanks.

 

My 88' T2 did it a couple of times when it floods. If you wanna fix it right on the spot rev up to about 4k rpms and turn the car off and on quckly. The tach will jump right up tp where its supposed to be. I don't know what causes it or how to fix it for good but this will work for when you need to know rpm's.

 

I have an 88 n/a and it does the same thing. When I turn my car on the tach does not work. All I do is (while the car is running) turn the key to the off position and back to the on position really quick and my tach comes alive. This doesnt bother me nomore but if someone knows how to fix it, I'll be one of the first to do it.

If anyone knows how to fix this, help us out.