Its a 99 Dodge Ram 1500 with 5.9 gas engine w/ 115K miles.
The truck started running really rough and I was 60 miles from home. The issue was bad plug wires, dist cap, rotor. These items were heavily corroded. I was able to get the truck home and then replaced the typical tune up items. Truck was running good as new. I drove it around and everything seemed fine until I took it out to the highway. Runs great at low RPM but cuts out and cannot accelerate above ~3,000-3300 RPM depending on the gear. When I get to ~ 3K rpm it starts cutting out and surging and feels like I am riding a bucking bronco.
The CEL has been on the truck for a couple of years and I have not checked it due to mice chewing up my wires a couple years ago (the joys of country living). I never rewired up the OBD2 port. It has run great and gas mileage has been normal until last weekend. Funny part is when it started running bad, the CEL went off.
I have had suspicion that the catalytic converter has been partially blocked because it has made noise before it gets warmed up. My thought is that when the engine was running rough, my gas mileage went really low for that trip home. My thought is all the extra gas that ended up in the exhaust has finally killed the cat and now i have a significantly restricted exhaust.
I am open to ideas. My next step is to install a test pipe and see if that solves the problem.