Hi everyone

I've been looking through on the ST170 hesitation problems on here and im abit confused so i will explain what mine is doing.

when the car is cold its OK, after a while when it warms up about 4000rpm onwards it hesitates and starts jumping down the road and its getting quite bad and the Mil light keeps coming on but when i plug the machine in it doesn't come up with a code. I've replaced coil pack spark plugs and HT leads cleaned all ground wires, I am really puzzled on what it could be. It does have a decat pipe on which worked OK for a day.

any help would be grateful.