My Mustang is a 3.8 v6 1998 and has the same problem! The dealer fixed the PATS key and it is still doing the same problem. I recently replaced the fuel filter, spark plugs and spark plug wires but it is still doing the same thing. Someone told me to replace the fue pump relay but the relay location cannot be found. I just bought a Focus SVT
Fuel PUMP and I will install it on Saturday. Whether I fix the problem or not, I will let you know. Have you fixed yours??? Please advise.