Stubber when first start
 

I have a strange problem. When I first start the car and take off down the road it will stubbier for a second. It started when I took it in for some work (front bushings, ball joints and alignment) While in I did not know how long it had been sense the fuel filter was changed so I had him replace the fuel filter. You can let it set and idle for 5 mins. and it will still stubbier when you take off. It will only do it once after you start after setting for 5 to 10 mins. It is like the fuel system is getting some air in it and you must rev it to get the air out, After it stabbers the one time it is good to go until you shut it off for a while and start it again. It has new (rebuilt) injectors, new fuel pressure regulator and dampener, new throttle switch, mass air flow sensor and vacuum lines. I wonder if the one way valve at the fuel pump could be bad and letting the pressure back off? It only does it once and after that it is fine. Other than that it runs fine, Idles a little rough when cold but smooth as silk when warm.
Any ideas?

If you think it is fuel pressure related, check the fuel pressure with a gauge.

Let us know what you figure out.

stubbier?

I doubt it would be because of the fuel pump check valve as the fuel pump should be strong enough to maintain fuel pressure - this valve is primarily to maintain pressure after the car is shut off.

You might check the fuel screen at the bottom of the tank.

You mention that it idles a little rough until warm - this could indicate a vacuum leak which could also be contributing your problem.

I agree with 944 Ecology - get a gauge and check the fuel pressure (both with the car on and after you shut off the engine).

I believe he meant "shudder". If the pressue is fine then look at the DME/ECU. A chip is available to fix it now for the early 944 shudder issue.

Dal

Tell me about the chip available to fix the shudder, stubber or what ever and where I can get one. I have ordered a new nut for the fuel rail. I will drill and tap it and connect a preasure gauge to it. I don't think it is a vacuum leak, I have replaced all vacuum lines with new ones and checked all the connections. I have took the intake off and replaced the gaskets, rebuilt the throttle valve. This problem is strange, you can let it idle for 5 mins before you take off and it still does it. It will only do it once and then it goes away until you turn it off for a while and restart it and it does it again. It seems like it needs cleared out and then it's ok. It don't seem electrical, but I am not ruling it out. The rough idle when cold I think is the auxillary air valve, it is the only thing that I have not replaced. It only needs to run for 1 or 2 mins before the idle smooths out. That don't seem to be a big problem.

This will be my last post on this as I am leaving the forum.

www.frwilk.com

I wish you the best and good luck!

leaving? pour quoi?