I had a strange occurrence today with the tachometer on my 96 XLT (147K miles). Driving along at around 35-40 mph, car running fine, I let off the gas and noticed the tach needle dropping. Funny thing is, it kept right on dropping down to zero rpm. The engine was still running, no stall or stumble or anything out of the ordinary. When I accelerated again it went right back to normal.
This happened 3-4 more times before I got to work. There was a slight drizzle and the air was pretty humid, but the roads were basically dry so I doubt this was a factor. This afternoon coming back home, I didn't notice it happening at all.
I assume there is some electronic sensor somewhere that controls the tach reading. Could this be the problem? Where is it? What to check? Any suggestions are appreciated.