Surging rpm While cruising

[fadetoblack188]

Truck is gunna be the death of me.

I have developed a surging rpm now while driving down the parkway.

Even with cruise control on at a consistent speed in the same gear the rpm’s will just sit and bounce like a heartbeat over and over consistently . Like jump 200 rpm rhythm I can hear it as well as tac jumping

Any idea what could be causing this. It was happening last week for a day then stopped. But now happening again

 

[jws123]

How many miles on it and did you scan it for codes? Also put it into tow haul mode to disable MDS see if it still does it.

 

[fadetoblack188]

It has 156k. Had a check engine light for a fuel level sensor. Comes on when I go below half a tank. Needs a sender. Otherwise no codes

 

[fadetoblack188]

How many miles on it and did you scan it for codes? Also put it into tow haul mode to disable MDS see if it still does it.

It has 156k. Had a check engine light for a fuel level sensor. Comes on when I go below half a tank. Needs a sender. Otherwise no codes

 

[fadetoblack188]

Hmmm now these codes

 

[fadetoblack188]

those codes unrelated i know why i had those its from changing the fluid with the rear jacked up ..

but still chasing this rpm surge while driving gremlin

 

[Soaringcook]

Did you find out the cause for this issue? Mine just started doing the exact same today when i towed a small utility trailer. I change my differential fluid 3 weeks ago, same with tranny fluid

 

[jws123]

Did you find out the cause for this issue? Mine just started doing the exact same today when i towed a small utility trailer. I change my differential fluid 3 weeks ago, same with tranny fluid

check your trans fluid level since you just changed it and did you use OEM fluid?

 

[Wild one]

Did you find out the cause for this issue? Mine just started doing the exact same today when i towed a small utility trailer. I change my differential fluid 3 weeks ago, same with tranny fluid

To check the 8 speeds fluid level,follow these instructions,especially the very first highlighted paragraph.You need the rear tires roughly 9" in the air to level the transmission.