Hello, I am a new member, I live in CA and have the following issue with my convertible 2001 gt stang. I had the low coolant level light come on and after filling up the fluid I erased a pending P0455 code. since trhis is the only way to erase the low coolant level. the next morning I took the stang to get smogged, it passed both low and hig dyno tail pipe tests, but failed because the computer was NOT running any of the 5 diagnostic systems. The tech told me to put 50 miles and then bring it back to re-test it. I am triyi8ng to be proactive and since I had a P0455 last year that just went away by itself till now, after replacing the gas cap, I also had overfilled it. I have traced all the hoses anf lines from engine to fender valve to gastank to left rear cannister. also the rubber seal between filler and tank. I replaced the vacum hose that goes from the intake manifold to teh fender valve. and seinvce I had bought a 10 dollar AutoZONE gas cap, I went to my local dealer and spent the 35 dlls for a ford gas cap. I am going to drive the 50 miles or more before I take it back to the smog shop. I was wondering is any one knows what else I could check, and has anyone ever experienced issues overfilling tha gas tank. Thanks a bunch. I will post after 50 miles to let you know what happens.