When we start the 944 cold (summertime cold anyway) the engine catches within a crank or 2 but will kind of chug and shake for the first 7-10 seconds and then settle into a nice idle at about 1000 RPM. DOesn't do it when warm/hot.

Is this typical or should it fire and run nice and smooth??

Just done:

Belts, plugs, water pump, All vacuum hoses, etc...

 

It could be a fuel pressure regulator.

 

could just be the humidity...moisture in the motor.

 

Did you make sure the vacuum lines are all in the correct place?

 

Yeah, that is all OK.

 

I had this problem and it turned out to be a head gasket leak. Car ran fine otherwise and did not smoke, but when shutoff, coolant would leak into the cylinder(s) and cause hard starting for a few seconds after it had sat overnight.

Could also be the ISV although it is completely removed on my brother's 944 and above 70 degress or so it seems to have almost no effect on startup/idle. When it is colder he has to crack the throttle to keep it running until it warms up.

 

Currently having the same issue. BHG

 

How is the car running once warm? Good power? Accelerating OK?
Where is the temp? Is it running hot?

 

I'd look at the ISV... found it out mine would do that then eventually it would only stay running for a few sec and shut off when idleing, so stop lights were a nightmare lol

 

Engine runs at a normal temp. Good powah and nice idle after running for 20 seconds.

ISV was cleaned when we had the manifold off. I didn't test it or check operation. Warm idle is fine, nice and smooth. Just the initial start it does a few shakes and chugs. I'll try to video it for better description.

 

I heard that once your car is warmed up on idle is doesn't use the ISV... could be wrong dunno. If you can get to it I'd test it along with the TPS... couldn't hurt anyway multimeter is our friend with these cars lol

 

Any chance the DME internal resistor for warm up has blown?

 

I bet its the turbolator...

 

mine did that and it was the fuel pressure regulator was unplugged from vacuum. Also try unplugging the ISV and see if it still does it.