I have been dealing with fuel system issues now since day one. I purchased my 986 in November 2011. The very first day I heard a howl from the fuel filler area. For 6 months, I would occasionally hear the howl and also get a P0442 CEL for a minor evap leak. I read a bit about it during that time but never came to anything conclusive. It didn't affect performance, but I knew it would be something to be dealt with sooner than later.
Turns out it was sooner... The past 7 months now I have been having major fuel system issues. I have researched everything I can think of including Diagnostics manuals, Durametric, Pressure tests, etc. but I cannot figure out my problem. I feel I may have multiple problems in the fuel system.
List of symptoms:
-very rough idle most of the time, the whole car shakes, a little gas and it smooths out
-howl sound has moved from the fuel fill area to the area around the pump under dash (only howls when starting or turning off vehicle)
-gas mileage is terrible
-major loss in performance (sometimes it runs better than others but I haven't found a common denominator)
-occasionally engine will rev higher than input of the throttle. It's a sudden change and the DME quickly adapts the FT's
-CEL for Major Evap Leak (P0455)
So far I have done the following in trying to diagnose this. There are so many valves it could relate to, and I just hate to keep "throwing parts at it".:
-Replaced fuel pump relay
-replaced fuel pressure regulator
-cleaned injectors, manifold, etc
-replaced AOS
-replaced oil filler tube
-removed and inspected fuel pump
-removed and inspected charcoal canister/vent valves/vent lines
-removed and inspected fuel pump
-tested fuel pressure at rail (I have video footage of the gauge...)
-durametric- I have video footage of various readings like fuel pressure difference, fuel trims, etc, while it is idling poorly, but could find limited information regarding its meaning)
The fuel pressure diff will climb until it reaches 40ish and then drop to 5-8 and start building again. Is this normal? This was not listed on the nominal durametric values.
Fuel trim is -2.00 for the long term... This is way off of the nominal value.
I completely removed charcoal canister, valves, etc, and have been venting into the wheel well the past two days to narrow the problem. It seems to have not changed anything. It stills operates with as inconsistent performance as before. I read some post about boxster race cars just removing the system so I figured it couldn't hurt for a couple days... I plan on reinstalling it though for the sake of the CEL.
I hope I have covered everything. It's late and my mind is shutting down for the day so let me know if I missed anything. It's a 2000 2.7L. 5 speed. Thank y'all all for your insight. I am ready to have her running like a top again!
Link to durametric video https://www.dropbox.com/s/6a2p94usfyjuc50/summary.mov
Link to video of fuel pressure gauge (sorry it's a little dark) https://www.dropbox.com/s/uzmtog3c8nkn4n0/Fuel%20Pressure%20Gauge.mov
Thanks so much for your help!!