i just purchased this car and drove 6 hours home with no issues other than i kept smelling fuel after filling up. i let it sit for about 2 hours and was going to take the kids for a ride when it stalled backing out. when trying to start it acts like it wants too but is surging and blowing a small amount of grey smoke out of the exhaust. i just checked the codes and only one is showing P0455.
2001 mustang GT 4.6
Kenne bell supercharger kit with Boost a Pump
30 LB injectors
That code is for a large evap system leak, which is where your gas smell would be coming from. Could be a simple as a leaky gas cap or it could be a deeper problem.
You really can't expect a 21-year-old car with those kind of modifications to be reliable. What do your spark plugs look like? Are they carboned up, maybe even wet, from excess fuel? Any codes?
https://www.obd-codes.com/p0455
https://www.youtube.com/watch?v=Ru8A7aYCUM8
i kept smelling fuel after filling up.
that's often an EVAP problem.
it stalled backing out
another EVAP symptom
only one is showing P0455.
well that confirms it don't you think.
A quick web search provides the code definition, along with troubleshooting steps:
P0455: Evap System Large Leak Detected
Change your gas cap , tighten it down correctly, and hopefully that helps.
If not then you need your EVAP system diagnosed (clogged vents or charcoal canister, blocked or stuck solenoids/valves, etc.)
A 5 second search of Scotty's Youtube channel I did for you yields this beauty:
https://www.youtube.com/watch?v=Ru8A7aYCUM8
https://www.obd-codes.com/p0455
https://www.youtube.com/c/ScottyKilmermechanic/search?query=evap
Thanks Joe ill check this out