High idle and poor starting

[weazgti]

I have a 2.7 944 that starts ok every day but sometimes needs a bit of throttle to start and i have to hold it to stop it shakeing itself to bits due to a low idle speed. After about 30 seconds it will be fine and run ok but when its warm it will idle a bit too high (about 1200 rpm)
Does this sound like the fuel pressure regulator?
First thing i did when i got the car was change the blue dme sensor with a genuine one but this didnt help.

 

[JamesO]

Idle valve may be sticking/failing if it runs normally otherwise.

 

[weazgti]

ill check that out. It does seem to be a bit jerky on and off throttle and stinks when i get some speed up (not oil burning) so its not running that great.

 

[peanut]

check your engine temperature sensor is within tolerance or the ECU will be enriching fuel delivery for too long and the engine will run over-rich. basically your cold start mechanism will not switch off. if this was the case you should smell the excess fuel and the plugs will show it too plus the engine will be a bit smoky and the fuel consumption way up

One or more of the injectors could be leaking ?

As a test try unplugging one of of the electrical connectors to an injector and see how it starts and runs. It won't be great but any improvement would confirm an over-fueling situation