my 2001 v40 (mitsubishi gdi engine) had an erratic tickover from the time I bought it, but developed a missfire after the bottom radiator hose fell off and dumped all the coolant on the road. My wife was driving it at the time and just managed to get home. I removed the engine complete, as it needed a decoke, and a cambelt change anyway. I did this work, reground the valves, changed the clutch and the water pump at the same time, and rebuilt the engine using new gaskets, seals etc. All mechanical parts appeared to be like new after cleaning, despite being run for 129000 miles. After the rebuild, the missfire was still the same, cylinder 2, and sometimes 3 as well. The plugs and coils have been changed with no difference. The ECU was sent away for testing and came back NFF. The injectors have been checked and cleaned, with no difference. The local garage has now had my car for 2½ weeks, because I had had enough, and they are completely stumped. A local independant Volvo specialist has looked at the car, and connected it to their diagnostic equipment that connects to Volvo's system, and the only thing they can tell us is the throttle position sensor is faulty, apparently. Could the problem be fried wiring? Can someone please help! This car is driving me mad.

 

Has a compression test been performed?

 

Yes, several compression tests have been done, all fine. Could the problem be a temperature sensor, or dare I say it, a throttle body fault? Why would it develop a missfire following the coolant loss? I'm stumped.