When I am cruising down the road doing say 25-35 mph, and I let off the gas to slow down or as I start to go downhill, the engine will quickly rev up about 50 rpm or so before it drops down. At first I thought I might be pressing slightly on the pedal before I let up, but I'm paying attention and I'm not, I'm just letting up on the pedal.

 

the truck will downshift on deceleration, this is most likely what it is, this extends brake life

 

I don't think it is downshifting at this point, it should not downshift until the speed drops enough. It does it each and every time I let off the gas pedal. This is just a quick 50-60 rpm or show jump.

 

Could it be the other 4 cylinders kicking in? I notice my truck usually goes into fuel saver mode as I let off the gas and begin decelerating/coasting, but once my speed gets low enough, the fuel saver mode turns off and I'm back to running on all 8.

 

I don't know. I have a December build with the locking tailgate, but missing the MDS light.

 

I have noticed with MDS kicks in my RPMs drop 50, so, good guess, MDS is turning off.

 

Yes, it's normal. If I'm not mistaken I believe you are seeing the torque converter unlocking.

G

 

I was just at service getting some Rapid Response items done, and this is what he said as soon as I asked the question. Thanks.