Hey guys just bought this 88 s10 blazer 2.8 4x4 with 114xxx org miles. Driving it home on the highway around 55mph it would fall on its face and bog down, i would have to floor it for it to go away. Did a basic tune up, icm, cap, rotor, wires and 3 spark plugs lol. 3 of them are super tight and stuck. I mixed up some of the wires and had to bring cylinder 1 back up to TDC. It runs again and drives fine on backroads but highway speeds are so bad when i floored it to maintain speed it started to overheat a little.

 

and no check engine light

 

possible clogged cat?

 

Got the cat off and seemed to help a bit but still at 55mph the whole truck shakes and i have to floor it to get it cleared out and after doing it a few times i noticed the truck getting hot.