Flooding after Fill up
 

My girlfriend has a 2004 with the 2.2 ecotech that dies at the pump every time she fills up. It won't start for 10-20 mins, but if she holds it WOT it will fire right up - indicating flooding. I've already changed the purge solenoid with no such luck. My next guess is leaking injectors, but how do I best go about narrowing it down to a specific one if it is? Going to test FP at the rail this weekend and see what we have. Any other ideas?

leaking injectors seem very plausible. if you see leakdown after the fp check an injector balance test will locate the leaking injector. Unfortunately to check this a tool to "pulse" the injectors for a precise length of time is needed. the dealer uses an active fuel injector testor or afit to perform this test. Not sure how to diagnose it without one. have seen a tester by otc for $124 at autorepairmanuals.biz

FP holds steady at 60psi both idle and WOT. After shutdown, it immediately fell to 56lbs and stayed there for over 20 mins. This tells me leaking injectors aren't the culprit. Furthermore, I was able to pull current code PO496 (EVAP Sys High Purge Flow), which leads to the Purge Solenoid....which I replaced 2 weeks ago. This could also be set by the gas cap, but I cant imagine why a faulty gas cap could cause flooding when filling up. Back to square one. Any other ideas?

Well I'm new to these cars but wiring seems to be a reoccurring problem. Might the harness have a short? Check voltages on the plugs or disconnect the solenoid and see how the vehicle operates. If there is no change in vehicle operation you may have found your culprit.

P0496 means there was vacuum in the fuel tank with both EVAP purge valve and vent valve closed. Is it equally hard to start after reinstalling the gas cap without actually refueling? If the trouble code is current, a shot of fuel vapors may be entering the intake through the leaking purge valve after the pressure inside the fuel tank is equalized with the outside.

No such luck with the gas cap. I pulled it off as soon as she got home, left it off for a few minutes, replaced it, and it fired right up. It did sound like the fuel tank was expanding or contracting slightly after it came off. There was definitely a smell of vapor when I took it off, but no apparent hissing of pressure escaping or entering. I will try a few more times throughout the week. I also cleared the code on Sunday, and it hasn't returned yet.

do you have access to a scan tool that can monitor fuel trim and 02 data prior to and during the no start.

No, its not supported my mine unfortunately. After removing the gas cap last night, it died in the driveway this morning and threw the same code. Regardless of whether it is the culprit, I'm beginning to think a new gas cap is going to be on the way. It still doesn't explain the flooding after we fill it up. If that was the case, theoretically I could leave the cap off permanently and that would fix the no-start/stalling, indicating a faulty cap. I'm becoming more and more confused, however.

Fixed it!
 

Come to find out, it was a faulty purge valve. Solenoid was fine. I also replaced the gas cap while I was at it. Seems to work just fine now.