I have a 1988 944, my problem is when starting the car with the engine hot or cold, it starts up with rough idling for about 3-4 minutes after that all is well, any suggestions would be appreciated.I already changed the air filter, cleaned intake manifold, also added Techron.

 

Change the fuel filter and pull the TDC sensor that is located behind the engine block on top of the flywheel housing. It sometimes gets sludge on the bottom of the sensor.