I have a few more posts in the past few months about this continueing problem, and dman I hope someone can help...

Symptoms- Several starts in the A.M. to keep it running, when it stays running it is rough at idle, and you can see the engine shake. At highway speed it runs great if I am not towing. If I tow it has low power and frequently you can hear the valves. I am only towing a 19 ft boat on a trailer, max gross weight is under 4200 lbs. I have a 3.08 or 3.11 rear end, I can't remeber which but ut wouldn't matter. I ma rated by Ford to tow over 5000 lbs. At idle I can manually open the throttle under the hood, it smooths out but you can still see some shaking of the engine. The only code I am getting is a continuous memory code 62 [torque converter not locking up]. I think this ais a symptom caused by whatever the engine problem is. I get an 11 for KOEO test, and no codes at all running.

What I have done- Last 3 months, I have replaced front fuel delivery module, egr valve, throttle body gasket, intake manifold gasket, TFI module, ACT sensor, coolant temp sensor, throttle position sensor, air filter, fuel filter, wires, cap, rotor, fuel pressure regulator, thermostat [don't ask why ] and PCV valve. I have cleaned the IAC valve,installed an EGR restrictor plate,and sprayed every seam and hose looking for a vac leak.

The only possibility in my feeble mind is a clogged cat. My plan is to cut the rear cat out and replace with 2.5 inch straight pipe. It sure seems like a vac leak, though. I am totally stumped otherwise, and I need some help from some of the 300 I-6 gurus out there...