Glad I found this board and a big thanks to all the information I've found here so far, and the knowledgeable people on here.

I recently bought a 96' Blazer, 4.3 engine. The trouble is, nothing major actually, the tach doesn't work at idle. When the gas pedal is pressed down, the tach works but I am unsure how accurate it is. In a nutshell, give it gas, tach works. At idle it returns to zero.

I searched the forums and found some information, mostly on aftermarket tach adjustments. So the question is, and I am sure it has been answered before and I can't find the link, is there an adjustment on the factory tach, so it works at idle, or does the whole instrument cluster need to be swapped out to fix this issue?

Thanks