More strange engine issues...

[kbod]

Originally Posted by blue62

A major clue I see when reading your post is:
"When filling with fuel the car does not start without mashing the pedal while cranking"
So on a modern day car "mashing the pedal (throttle) just gives the engine more air.
The DME/ECU gives the engine gas.
So your fuel air mixture is to fuel rich after fueling so it will not start until you give it more air by "Mashing the Pedal"
So my guess is that you have an issue with the EVAP system. bad purge valve or the like. An EVAP purge valve stuck in the open position allows fuel vapors back into the intake. So it causes a to fuel rich situation after filling up.
EVAP systems can be a PITA.
Your stalling when coming to a stop can be caused by this same situation.
or.... a vacuum leak.
Have you done a vacuum test with a proper vacuum gauge???

First id like to thank you on how helpful you have been ever since I bought this Boxster, now for the evap system, I took off the passenger fender liner and replaced the 2 solenoids along with the charcoal canister, so for the evap system that leaves the lines themselves along with the solenoid under the intake manifold. I suppose my next move is to first do a smoke test to see if there are any post MAF vacuum leaks, then if nothing obvious shows its to test the evap valve under the throttle and presumably replace those. While the little vacuum hoses have all been replaced the vacuum canister and solenoids haven't so those might be an issue. I was also considering the possibility of a leaky injector? but that would probably throw a MIL

[blue62]

Originally Posted by kbod

First id like to thank you on how helpful you have been ever since I bought this Boxster, now for the evap system, I took off the passenger fender liner and replaced the 2 solenoids along with the charcoal canister, so for the evap system that leaves the lines themselves along with the solenoid under the intake manifold. I suppose my next move is to first do a smoke test to see if there are any post MAF vacuum leaks, then if nothing obvious shows its to test the evap valve under the throttle and presumably replace those. While the little vacuum hoses have all been replaced the vacuum canister and solenoids haven't so those might be an issue. I was also considering the possibility of a leaky injector? but that would probably throw a MIL

A smoke test will only show you obvious vacuum leaks.

Smoke tests cannot test vacuum on the down stream side of a one-way vacuum operated valve.
Such as the one in the SAI system.
So for example a smoke test would not detect a vacuum leak in the SAI vacuum canister.
A vacuum gauge only costs around $20.00-$25.00
Anyone who tinkers with cars should have one and know how to use it.
They are a very useful diagnostic tool.

[kbod]

Originally Posted by blue62

A smoke test will only show you obvious vacuum leaks.

Smoke tests cannot test vacuum on the down stream side of a one-way vacuum operated valve.
Such as the one in the SAI system.
So for example a smoke test would not detect a vacuum leak in the SAI vacuum canister.
A vacuum gauge only costs around $20.00-$25.00
Anyone who tinkers with cars should have one and know how to use it.
They are a very useful diagnostic tool.

I ordered a vacuum tester but I have a whole new issue, so the car runs fine on cold start although the other day I got a P0410 and P1411 Code on cold start, other then that it drives fine but when I come to a stop the idle dips way down and comes back up and it runs a little rough and vibrates at idle. sometimes when I come to a stop it will stall but comes back to life, the other day I got to a stop light and the car stalled and would not start up no matter how much I tried with pedal or anything, it was completely dead, the tachometer did move so I dont think its a crank sensor, but after having the car towed home and sitting for a few hours it started right up as if nothing ever happened. Would this along with my issues at the gas station indicate a fuel pump failing? Im not sure if a simple vaccum leak would cause these conditions