I have a 3rd gen cummins with 150k 0n it. When I let it idle on cold days for warm up or letting it idle on hot days for maybe 10 mins. When I put it in gear to take and give it fuel it lunges. I swapped fuel types around and I run a fuel addiative but it still does it some but not every time. I was wondering if it could be the torque convertor trying to lock-up? Any suggestions would be great.