Archived intermittant loss of tack/OD

[Archive]

I have a '95, 3500 w/auto trans (120K). Intermittently I lose the tack, OD, cruise & AC. Sometimes just turning it off, waiting a minute and restarting makes it all right again. Often not! All fuses (dash and under hood) seem OK. Seems like it might be some sensor?? Because it is intermittent, it's extra frustrating. Getting stuck driving 45-50mph is annoying. Anyone have this problem before? Please help! Thanks.

 

[24VChev]

The crank sensor may be out of adjustment. Look down at the front of the damper the sensor is off to the passanger side at about 11'o clock. The gap should be about the thickness of a business card or less. This would effect the Tach/OD and cruise but not the A/C. Does the Alternator stop charging also? Could be a PCM problem if it does.



Good luck



Malcolm

 

[cerberusiam]

 This would effect the Tach/OD and cruise but not the A/C

All of the above would be effected by the CPS going bad or out of adjustment. There should be a plug towards the top front of the block that can cause connection problems plus pay attention to the routing of wires past the belt and make sure there are no rubbed spots. Get yourself some dielectric grease and work the connections over as that is also a source of problems.

 

[Missouri Mule]

Check the engine speed sensor(crank speed sensor) connector it could be dirty or have bent pins.

Also other members had to add new ground for the sensor to cure problem.

 

[SCosgriff]

I had the same problem on my truck. It was heat related and only happened when the truck got warmed up. I had also just put the Banks exhaust brake on which created more heat by the PCM. Replaced PCM and have had no problems since. First I would check the connection into it.