98 mustang cobra
 

my friends 98 mustang cobra.. mostly stock except gears. anyway when he tries to start the car it wont start. were assuming its a fuel problem, if you turn the key off and then to the on posistion a few times 3 or 5 then try to start the car it will run for about 3 minutes then it starts to die out. sound like it has a miss but i think its lack of fuel pressure, eventually after stumbiling for 1 minute or so it stalls out and stops and wont start agian untill we mess with the key.

my other question would be could this be a computer issue.. i know that when the motor is running cold it runs rich and idels higher. i was wondring if the computer was going into lean condition and causing this problem. is there a way i can trick it into thinking the motors cold ans see if this helps.. other then pull the wire to the sensor cuz i figured that but i didnt get a chance to mess with anything much yet.

anyone have any ideas to help figure it out. also theres a new fuel pump..pickup and i checked codes...it reads that the o2 sensors are bad but could that be because of the lean condition from the computer? or is this a faulty fuel pump. thanks guys

to me it sounds like the fuel pump is priming when you turn the key off and on, but not on when the car is in the on position, either ignition switch, or fuel pump could be going! can you hear the pump prime when you turn the key off and on?

i think i can hear the pump prime. anything else it can be other then the pump. i think its a new pump installed 6 months or sooner ago. not exactly shure. anything else i can try to be shure.