And it just died....
 

My brother just bought a new (new to him) Mustang. It's a 1991 LX 2.3L Notchback 5 speed. I was working on it to get it running again. Well, the previous owner had the entire dash and center console ripped apart and in the trunk. I put everything back together and didn't have any problems. Well, get this..... I got it started and drove it for a test drive. I noticed that the tach didn't work and I had a "check engine" light that stayed on (no flashing). Then futher down the road, the car just died! After coasting it to a stop, I started it back up and instantly the tach works and the light is off. Weird :rolleyes: Well, I drove it back up in the garage and turned it off. Then started it back up again and the tach doesn't work and I get the light. I also ran the computer codes and the light just sitts there on. It's suppose to blink. What gives? I can't figure it out! Also, I noticed that there wasn't a spot on the back of the gauge cluster for any wires or plugs for the tach. I thought that was weird. This was the first Mustang that I saw with the dash tore apart like that. I am supprised that I was able to put it back together. I am even more impressed that all the parts were still there :D What is the problem and how do I fix it?

You need to start by checking and cleaning all the grounds. You need the MIL to function.

Take care,
-Chris

Bad Ground
 

That sounds like a textbook intermittent ground. Unfortunately, they are the biggeat pain in the butt to troubleshoot. Grab your meter, time for continuity checks...