There's a TSB for P0442/P0455. (Small/large evap leak.)

It basically gives along list of places it could be leaking and wishes you luck.

My P0455 was the purge valve.

I now have a spare perfectly good used yellow gas cap.

 

So what do we have?

 

Don’t know , we’re waiting for a report after the new purge valve is installed

 

I installed it Wednesday morning, cleared the codes. Drove it back and forth to work Wednesday and Thursday and all is good. Thanks a million guys! ChevyHHR.net Rocks!!!!

 

Good move with the AC Delco part. I (unnecessarily) replaced my OEM item with a Duralast from Autozone. It failed in a couple of years. Put the OEM back in, then returned the Duralast for replacement under Autozone's lifetime warrantee.

Miraculously, I had kept the receipt. Don't know if I really needed it. Now I have spare purge valve I'd rather not use.

 

Glad you got it fixed, I had that counterfeit AC Delco a few years ago from Amazon, I got a refund an ordered AC Delco part from RockAuto, it’s still working 4 years later.

 

Well, I made a trip to Dallas this morning and here we go again. P0455 again! So far I have changed the evap vent and the evap valve. I think I am gonna pickup an ac Delco gas cap and give that a try next. My driveway is at a slope, whenever I fill up with gas I have to park it with the rear of the car the highest, if I park with front of car highest then I smell gas the next morning. Never see it on the ground or anywhere, but definitely smell the vapors. When car is half full it does not smell.

 

When you cleated the codes tou reset all of the OBD tests; the EVAP tests can take 14 days to run. There is no need to clear codes they clear themselves when remedied..
Smell of vapor comes from a leak like a rusted vapor tube or a bad gasket on the tank.

The Duralast valve I got had identical die marks as the OE one that was replaced. I had no problem with it.

 

Crawl under and look up above and behind the rear axle beam, see the foil heat insulation, is it wet with fuel? Then replace the fuel and vapour lines.


This stuff absorbs most of the drips

Up there see the corrosion

 

Ah-HAH. NOW you mention the gas smell. Betcha when you get under there you'll find a rotten evap line.