Truck stumbling... stuttering...

[RGSMDNR]

Thanks all, Ill look into that.

[RGSMDNR]

Diggin up an old thread, but its doing it again. It only does it when Im using a custom tune. This time I was using the econo tune. It also seems to be getting worse. It would go away after driving it but now its staying while driving down the road. Had to pull over and reprogram back to stock. Why would it only do it while in a tune? Everything seems tightened and clean.

[Longshot270]

My next guess would be fuel system.
Where are you filling gas? What brand are you using?
Fuel quality has been known to cause issues also. I'd try mixing in some premium and see if that improves it.

[RGSMDNR]

I fill up at Costco so not sure where they source their fuel from. Im also running a 89 Octane tune but 87 fuel and am turning the timing back 1 degree as per required.

[Longshot270]

Originally Posted by RGSMDNR

I fill up at Costco so not sure where they source their fuel from. Im also running a 89 Octane tune but 87 fuel and am turning the timing back 1 degree as per required.

Ok, go to Shell or another top teir brand. Not all fuel blends are equal. 9 times out of 10 it pays to spend more per gallon more for higher quality fuel.

For me it means up to 1 mpg difference...or nearly 10% increase in mileage for spending 1% more in price.

[RGSMDNR]

Ill give that a shot. thanks.