I've got a '93 SR5 Ex-Cab 5-spd 4x4 3.0 and the tach is very intermittent right now. When I go over bumpy terrain sometimes it starts working and just about everytime I go around a sharp right hander it starts to work again. And, everytime the tach cuts out, so does the a/c. The fan keeps blowing but the air is not cold. If I leave the dirt road and the tach is working then it tends to keep working for a awhile...?????

I've researched that the tach gets it's signal off the igniter and all those connections looks good, and that there is some signal the a/c needs off of the tach for it to run, so it makes sense that when the tach goes, so does the a/c...but why is the tach cutting out?

HELP!!???