My truck is feels like its skipping or missing when I accelerate at 50+ mph/1200-2000 rpm. Just had plugs replaced, injector cleaned, and Transmission overhalled. It mostly happens when going up hill, ocassionally on flat terrain. Nothing happens at sustained speeds on flat ground, it will occasionally do it when I try to maintain around 50mph on an uphill. It goes away if i take my foot off the accelerator and then re engage. it will also go away if I use more power.

 

Possible fuel pump is bad.

 

Check fuel pump module on frame behind spare tire for corrosion

 

Its not a fuel pump or module. You have a misfire, could be a cracked plug or another bad coil. You need to find out which cylinder it is or you will be replacing the cat converters too.

 

bought two new coils, (duralast). relpaced Coils 6 & 8. Made the problem worse.... it is also idling at 800-1000 rpm on start

 

You need to do REAL troubleshooting, or all you'll do is waste time and money.