The missfire came on suddenly, at first only under load over about 3500 RPM, but gradually got worse until the car runs a bit lumpy at idle, and stutters at anything higher. The car still starts first time, no problem, so I'm guessing the timing sensor is ok...I also think the car is running a bit rich because I could hear unburnt fuel popping in the exhaust when I lifted off the gas, and the exhaust smells mildly of unburnt fuel.The plugs are brand new.Here is my shortlist of suspects (in order of what I hope it is!):

1) HT leads arcing or a dirty connection.
2) Bad contact at the distributor.
3) A bad 02 sensor or dodgy MAF output.
4) A dying coil (not likely as it's one cylinder?)
5) A dead ECU...
6) A broken valve spring... :-(
7) A head gasket breach between 2 cylinders?Is there anything I missed? Does anyone know the best way to diagnose a missfire in a 944?

Generally?Help!!?By timing sensor, I meant the flywheel sensor... There is a notch in the teeth round the outside and that sends a negative and positive edge pulse to the DME. The sensor that picks this up craps out occasionally, but causes starting trouble. Not getting starting trouble, so I'm pretty sure that isn't the cause.

first do a compression check see if it is mechanical like that or not.
Then change fuel filters and maybe clean injectors etc.

The missfire came on suddenly, at first only under load over about 3500 RPM, but gradually got worse until the car runs a bit lumpy at idle, and stutters at anything higher. The car still starts first time, no problem, so I'm guessing the timing sensor is ok...I also think the car is running a bit rich because I could hear unburnt fuel popping in the exhaust when I lifted off the gas, and the exhaust smells mildly of unburnt fuel.The plugs are brand new.Here is my shortlist of suspects (in order of what I hope it is!):

1) HT leads arcing or a dirty connection.
2) Bad contact at the distributor.
3) A bad 02 sensor or dodgy MAF output.
4) A dying coil (not likely as it's one cylinder?)
5) A dead ECU...
6) A broken valve spring... :-(
7) A head gasket breach between 2 cylinders?Is there anything I missed? Does anyone know the best way to diagnose a missfire in a 944?

Generally?Help!!?By timing sensor, I meant the flywheel sensor... There is a notch in the teeth round the outside and that sends a negative and positive edge pulse to the DME. The sensor that picks this up craps out occasionally, but causes starting trouble. Not getting starting trouble, so I'm pretty sure that isn't the cause.
Call dave at promotion 305 542 1612 they build 944s

first do a compression check
+1!