I changed my stx cluster to a fx4 one last night. Before I changed it everytime I would be in cruise control and go over a bridge with a decent amount of elevation to it I could heat the engine start to sound like I was gunning it and I would imagine if I had a rpm gauge it would be increasing quickly. But going back down the bridge it would disappear. So on my way to work this morning I decided to do what I normally do and put cruise control on since its straight interstate to work. Well went over three bridges and the sound is gone and rpms stayed constant lol. I'm not complaining I'm just not sure what changing the clusters would have to do with that. Lol

 

Well now its doing it again

 

You're probably hearing the torque converter lock/unlock on the slight elevation.

 

Yea I hate the tc jumping in and out at the start of going up hills.... I tend to turn off OD when I travel on certain roads with hills....

 

well it shoots the rpms from around 2k to about 2.5 k at the peak of the bridge