I have 1999 2500 360 automatic that always shifted funny, well after 1 1/2 years it quit so I had a mechanic replace the tranny with a refurbished one. Thats when all the trouble started. ran terrible after that he thought maybe the cap and rotor, replaced that, replaced the cam sensor as well. It's cold here in the NE so he thought possible gas had water or it was frozen, so I picked it up drove it 1/2 mile and had to bring it back. Then he thought it may be the computer and he replaced that and still ran bad. Tried to replace the plugs and broke one off. Now I have a broken down truck with a great tranny....would shift great if it ran...... any ideas why the computer might go when the tranny was replaced. it backfires and has no power. Now I need to get the broken plug out before I can proceed. Had somewhat new wires but he thinks the plugs where bad. I guess my question is that it seemed to run fine before the tranny went so could the computer just go bad that quick, and i could see that it could be plugs but I just keep going back to it ran before the tranny Any thoughts on this would really be appreciated. Let me add the mechanic is working hard to fix this and he's just as unhappy as I am. Please if you have ANY thoughts I am desperate. Thanks in advance. Mike

 

More than likely what happened is he broke the crank sensor when removing/installing the trans. That would account for all of your problems.

 

I will second that crank sensors are nothing but headaches!! I had all the same problems then
swapped out the crank sensor and it ran like a dream.