i have a 1995 Chevrolet z71 5.7 automatic around 160,000 miles. About half way through a 4 hour road trip i noticed my truck starting to misfire while going uphill. As soon as i would start to travel uphill and the truck got a load on it (before it would downshift) i would start to miss. throughout the weekend i changed the following:
spark plugs
distributor cap and rotor
wires
sensor on top of the intake manifold...threads in really easy (cant remember what it was called, maybe the coolant temp sensor}
alternator (no specific reason why)
fuel pump
And still no fix. Its starting to do it more often, including at stop lights while waiting. It seems to be getting worse and i really need this problem solved. If you have any ideas i would be really glad to hear them. Thanks

 

Probably Injectors...clean or replace.

 

Just tossed some seafoam in the fuel...I had the breather off while I was replacing the dristributer cap and didn't notice either of the injectors acting like they were humped up but hey u never know may work

 

I guess that's ok stuff, I use Lucas in all mine. Not sure that the additive will fix your problem quickly though, it's sorta a slow process, more like a maintenance thing.

 

Ya I found another forum where the guy had his throttle control sensor and something else changed and it fixed the problem if by Friday this seafoam hasn't solved the problem guess I'll try that next