I'll try and keep this short.... I have a 03 crew w/ 155k 265 tires , 5" exhaust, ppe standard.

I pull a fiberglass 21' fishing boat that weighs approx. 5-6,000 lbs.

For normal driving, I usuall have my ppe set on #3 , which seems to give me my best mpg.

When I pull my boat, I have towed on both #3 and #2.

I don't like the fact that every time I want to tow, I have to take the time to switch between the two. I know its not too big a deal but it kinda sucks.

So here is the thing......... when I've switched between the two settings, I have noticed a difference in performance. I mean that when I have pulled on #2 and then go to #3 for daily driving and then back to #2 for towing. the #2 setting seems to act different??? For example: on a trip to a local lake, I was going up a decent size hill and the truck seemed to have plenty of power on #2 w/ tow/haul on. After that trip, I switched back to #3 for about a week of normal driving. Then I went to #2 to pull the boat on the same hill, I had to floor it and the truck had to really work and it seemed like no power to get up the hill. The hill is on my way home, so I would have about 100 miles on the tranny relearn.

When I switch levels, I do the tranny relearn. I had the inj. replaced about 3,000 miles ago. The fuel filter was also replaced at that time.

So, is this normal?????? Sometimes I have power and sometimes not.......

I dont have a diesel but I have noticed this also with mine. I attribute it to bad gas most times. Other times I attribute it to the truck having its own mind and nothing I do is going to change it. Kinda like my wife. :D