Intermittent Hard Starts

[Pianohawk]

After my 99 boxster is turned off and sits for an hour or two it has trouble starting again. It will crank but the engine does not catch. On the second attempt to start it cranks for 10 seconds and then slowly gets closer to fully catching until it finally does. After over $2,500 worth of repairs it still stalls the first time I attempt to start it.

I've replaced the crankshaft position sensor, MAF sensor, fuel regulator, fuel injectors, battery, and have repaired all vacuum leaks.

Does anyone know if replacing the gas cap will help? What else would cause a drop in fuel pressure while the car sits? What's HAPPENING!? lol

thanks for your help, thoughts, or comments

Colby

[extanker]

put fuel psi gauge on it ,note running psi,then shut the car off. you will need the spec from po but it should hold a min psi for x amount of time .if it fails this test suspect a bypassing check valve [that i have no idea where its at] this fuel system testing 101

[Pianohawk]

It's been in a great shop for the past three weeks. They did the fuel pressure tests while it was stationary and out on the road. Wasn't holding pressure. Hence all those replaced parts I listed in the original posting.

[Norminhouston]

Sounds like they are just replacing parts in hopes of finding something. I think I would hunt for a different mechanic. Parts changers can be expensive.

Norm

[extanker]

how fast does it get to dead head psi ? it should take a second or 2. leave the fuel psi tester on it for the 1 hr .is it holding psi? have they done flow/volume test ? on some early gm cars an amp draw for the pump can tell you a lot on the pumps condition. if its not holding psi for the spec time its going back to the tank but these pumps are/should be quick enuf to let it start after extended cranking time. dont overlook fuel pump voltage