I have a 2000 Blazer 4x4 4.3l auto. When I accelerate up a hill, about 50% of the time, the rpms will climb to over 3000, while the truck actually slows down. When I let off the gas, the rpms wind down VERY slowly. Transmission never shifts during all this. Two different mechanics have found nothing wrong. It never even acts up for them. What is going on?

 

I have the same issue at times, other times if i have cruise control on and go up a small incline on the highway the rpms jump past 4000, this is without a load, only the truck. Dont know whats causing it though

 

I'm thinking the bands in the transmission are slipping.

 

Could it be a fuel problem?