Hello Billy,
Thank you for your reply.
Yes, this truck originally had this kind of sensor. A strange one.
Actually the old sensor and the new one has 4 wire as well. But we have not calibrated the truck. We do not have a program for it.
So I guess this could be the problem. It is just seems to be strange that this tachometer could casued a sympthom like this.
Anyway, thank you again.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.