Quote Originally Posted by SlowNA06 View Post
Hey fellas. Scanned the '04 GTP tonight:

P0455 Evaporative Emissions System Leak Detected - Gross Leak/No Flow

No visible leaks or disconnections anywhere. Gas cap is in good condition.

So, do I have to replace a part? Take off the EGR and clean it (if so, best method?)?

Anyone have a general troubleshooting guide (checked gpona's manual, recommended some kind of smoke test to start troubleshooting... so I guess that would mean taking it to a dealership)... like a list of likely/cheap replacements or tests?

Thanks in advance!

Edit: Further research seems to indicate that the "evap canister vent solenoid valve" located in the driver's side rear fender gets dirty and can be cleaned by removing the wheel, wheel well, pulling the thing out, and hitting it with compressed air and carp cleaner. At least, I guess this is something that's almost free to try before throwing money at it. GM Part# 25932569 EVAP VALVE... in case I break or just need to replace it after all.

No time to do it until Saturday, so still open to suggestions.
I was having an problem with my EGR.. But I did what someone told me and all it good currently! I just sprayed the heck outta the EGR with carb cleaner and took a few Q-Tips and cleaned her out and it seemed not to work on the first run, but after a few mins a start and go, it came back to life and works fine for now.

So Clean it with some carb cleaner and grab some Q-tips and a few shop rags and go to town!!!