NC Hesitation in reverse when cold

[Brantman]

2008 GTPHT; Each day on my initial start up, when I begin to back out of my garage my car 'hesitates' almost as if someone pulled the emergency brake. This is a rather recent development and sort of coincides with an check engine code indicating a loss of pressure in the fuel system. (Normal cause is gas cap not tightened.) I've replaced the cap, but the light comes back on after a day or so...Anyone have any idea what could be causing either of these two events (if not both)? It does fine after that initial backing. I allow the car to warm up, but after 4 years, this has just begun. Mileage is approaching 58K. I had the dealer check it but they reported "unknown code". Funny, but Advanced Auto and my neighborhood garage get the same reading every time. Could be that it is under warranty sill?

[Brantman]

Really? No one has any idea? How about a swag?

[wildfire0310]

What's the check engine code?

[Brantman]

Po455 "gas cap" code. reset twice, bought new cap, reset again, came on again. The only other thing I have done recently is change the air filter with an after market job. ***** to wrestle into place.

[CaveRacing]

Maybe this?

http://forum.miata.net/vb/showthread.php?t=413060
or
http://forum.miata.net/vb/showthread.php?t=322315

[Brantman]

Oops!! I've had 7 Miatas in the last 9 years and I have ALWAYS filled them to the brim. Only had 1 CEL condition before on a 2000, and it ran forever with the light on. Something about "catalic threshold exceeded". Never did figure out what it was and no noticeable negatives in power, mileage or anything. This problem with my 2008 may well be the purge solenoid or EVA gizsmo. No problems starting any of them....ever. Best machines since SINGER sewing machines. I will, however, cease overfilling my 3 Miatas!!

[sharkythesharkdogg]

You might want to look and see if your car has a vapor purge/tank pressure solenoid. I'm pretty sure the NC's do. I've had a few later model NBs come in with this code, and the cap wasn't fixing the problem. It's not very common, but the solenoid was the culprit in the situations where the didn't get rid of the code.