2000 sierra 6.0 weird issues
I got about 10.1 mpg befor the tune, up to 11.5 now. Tuner says I should be doing way better with his tune.
The issue I just noticed is if I start the truck and drive I seem to be giving it a lot of throttle to move. From stop lights and everything.
I noticed one day after plugs, I drove on the highway(2000rpm), got off and hit a light, turned and gave it gas to make a yellow and felt like I got rear ended the truck had so much power. This lasted a day or two.
Yesterday after work I start the truck and gave it throttle in neutral to 1800-2000rpm. Truck drove like a 6.0 with 4.10s the way home. It usually feels like a 4.3 lol.
This morning I went to back out of my driveway and put it in reverse and feel like I'm giving it 15-20% throttle to move and with no throttle it won't move on engine idle. I put it in neutral held it to 1800-2000rpm, put it in reverse and boom, I just use the brakes to back up, No throttle. Truck drove like the beast it is too.
So what is up? Torque converter bad? Does the computer sense it's slipping and pull line pressure up? Tps sensor? I don't get it lol. Would a trans shop be able to tell me what's up?

