Still have a cat converter on your truck? Might try removing the front O2 sensor(s) from the exhaust, and see if it runs any better..... They can be fun to remove though.....

 

Or just unplug it?

 

If the cat is clogged, need to give a hole for exhaust to escape. So, needs to actually be removed.

Or, drill a small hole right before the cat, and put a pressure gauge on it. Shouldn't show more than about 2PSI of pressure.