Scotty,
I have a 2006 Chevy express 2500 van with 150K miles. I have a random misfire code that no one can figure out the cause. I had four different car repair guys check it out and I still have the code. While this was happening I had the right cat go bad so that was replaced engine code 300 still there. Yesterday I had the left cat replaced because van couldn't get out of its own way, ran terrible and I heard the rattle in the pipe that you mentioned once before. Any way it runs better know but the random misfire code is still there. Typical things like plugs and wires have been replaced.
New item, when van is cold, I put trans into drive and have to rev up engine before it will move. Than when it still is cool and I come to a stop the van feels like someone just rearened me and the truck stalls. it starts right back up and all is fine. Shifts fine when warm and drives ok the only code I have is the random misfire.
Any Ideas? there is no mechanic only "parts changer" around here that can help me figure this out.
You have a bad torque converter, replace and rebuild trans (I wouldn't pull a trans to put in a TC without taking the valve body off and inspecting trans...which leads to a rebuild).
Did the mechs check fuel pressure? Clean injectors? Check LTFT (so you know if there's vac leaks)? Check MAF and O2 sensors?
Your issue sounds two fold: transmission/torque converter and possible hydrolocking in the engine.
Have you checked for oil in the combustion chamber or oil/blue smoke coming from the tailpipe? Is there an abnormal amount of oil in the spark plug gallery? In rare cases oil build up in the combustion chamber, particularly oil that is out-of-spec (too thick) can cause a "hydrolocking" effect on the piston. Since it sounds like you've eliminated many of the common caused I would look here - it is just a hunch!
