Hey MICKM, I was having all kinds of weird problems with my digital 6AL-2 on my hemi cuda. IT was driving me nuts. Sometimes it was fine next time it would act up. It was mounted in the car under dash on the passenger side. Tried everything. It turned out it was the tach! It was only a year old but I replaced it with an auto meter and all problems went away. After fixing mine I've heard of several others having the same problem.