Little timing changes, little fuel changes, and other small stuff goes along ways. Thats why you paid for the tune, right?

 

the 4 cylinder mode is a joke anyway. it's only on when your engine wouldn't be using any real amount of fuel on all 8 and it's another system to cause problems. it's pretty normal for a good tune to get you better fuel mileage in addition to everything else.

 

Its a F'ing suburban! 4cyl mode is a joke ESPECIALLY in a 6k brick! I wont buy another suburban until they put a 6.2 option in them! The biggest problem i have with V4 mode is the fact that the truck slows when in v4 then jumps back into V8 mode and has to make up what the V4 lost. Probably a good idea in a RC 2wd on highway tires but pretty pathetic on anything else.

 

Its very common to turn it off for tuning. This is probably how he set it up. I turn it off all the time.

 

Is this a normal poblem for you? To tell people things and have no recollection of ever saying it? You may want to get that checked out. lol