Engine/Transmission (1998.5 - 2002) Tach moves ever so slightly during steady driving

[Silver Bullet Ram]

I have noticed this here lately, needle will move slightly up and down while driving. Does it sometimes, sometimes it doesn't. Truck seems to run fine.





Gary

 

[RustyJC]

The tach in my truck will move in about 20 RPM increments at steady speed as well. It has since the truck was new. I think it has to do with the tach being driven by the PCM - being digital, it probably gets its signal to display to the nearest 20 RPM or so.



Just my theory - it doesn't seem to affect engine perfomance at all.



Rusty

 

[Silver Bullet Ram]

Sounds like i am not alone then, seems like since i paid this thing off it breaks this or that alot here lately. Just wanted to make sure something else wasn't about to break... lol





Gary

 

[rkressg]

Mine has done the same thing since I picked it up 4 years ago (with only 11 miles on it). 100k later, still does the exact same thing. I think it is what RustyJC said, it is just a digital read out spit up in 20rpm increments that causes the choppy movement.

-Rich