Hi. I have a blazer 4.3l 4x4 that is having trouble while towing uphill. Issue is after about 1hr of towing truck starts to lag in power and will shutter then stall only going uphill. After getting on to level surface it starts and goes fine again.
Any thoughts and info can be a big help
Thanks

 

Problem solved as it was a very clogged vapor canister plus a dirty fuel filter. Clogged canister causing pressure to build up and choking out the motor
Tows great now