Hey, I got a friend with an 04 2500 cummins that when he revs up on it his tach goes all crazy and when he lets off it goes to 0 rpms. I'm thinking the there is a loose connection or faulty sensor but i was wondering where the sensor for this would be located. i'm supposed to look at it on sat. oh it only started doing it after he had injectors replaced in it.Any help on this would be greatly appreciated.

 

My 06 is doing the same thing.

 

I have an 06 cummins that is doing the same thing and i was told by my friend (a dodge mechanic) that if the sensor are ok then you have to replace the cluster in the dash to fix the problem you can not just fix the tach . this is a problem is some year models. also the the cluster are reman not new.

 

but which sensor is it?