I have a Ford Escort built in 1992 with 105 hp. Two weeks ago the stand gas was broken and I was in the workshop. They have a regulator valve installed. When I had the car again, he jerked off from time to time. Not always, but only sometimes so “hopping” for about 30 seconds. Then it was gone again. At the next ride everything was ok again. Then the whole thing started again. Most of the time it was when the car was cold. Now I was back in the workshop. I can’t imagine that because of the thermostat the car was jerking. When I went home from the workshop it didn’t jerk, but it may be that it comes back again, so I have to wait. Thank you very much for an answer.