Tach Question

[mxvet354]

While driving home last night with the cruise set on 75mph, I noticed my tach jumped from 2,300 rpms' to 2,400 and back to 2,300 a couple of times pretty quick. My rig is bone stock with the exception of 285's. Nothing else changed, the motor did not "spin up", volt meter was steady, I felt nothing from the motor or drive train. I just happened to notice the needle movement on the tach.

Any suggestions??

Thanks in advance
Curt

 

[ColonialRovers]

Did you ever find an answer to this?