2000 Mustang GT

[jimn411jm]

I'm having an issue that is puzzling me, my car runs great.....until I've driven it continuously for an hour or longer it starts running really badly, like it's not running on all cylinders. If I turn it off and restart it it will run fine for a few minutes then start acting up again. If I let it sit for several hours it runs fine like nothing happened. Any help would be appreciated

 

[Mustang5L5]

i would suspect either the fuel pump, or the ignition coils but you will need to perform some troubleshooting. For instance, I would get a fuel pressure reading when it's misbehaving and verify that pressure is correct. Are you able to hook up an OBD2 scanner when it's running bad and see if oyu have any pending trouble codes for a misfire, that might identify the cylinder?

ALso, whats the general state of the car? how many miles and when was the last time the fuel filter was changes, or are oyu over the recommended interval for changing the spark plugs?

 

[jimn411jm]

i would suspect either the fuel pump, or the ignition coils but you will need to perform some troubleshooting. For instance, I would get a fuel pressure reading when it's misbehaving and verify that pressure is correct. Are you able to hook up an OBD2 scanner when it's running bad and see if oyu have any pending trouble codes for a misfire, that might identify the cylinder?

ALso, whats the general state of the car? how many miles and when was the last time the fuel filter was changes, or are oyu over the recommended interval for changing the spark plugs?

new plugs

i would suspect either the fuel pump, or the ignition coils but you will need to perform some troubleshooting. For instance, I would get a fuel pressure reading when it's misbehaving and verify that pressure is correct. Are you able to hook up an OBD2 scanner when it's running bad and see if oyu have any pending trouble codes for a misfire, that might identify the cylinder?

ALso, whats the general state of the car? how many miles and when was the last time the fuel filter was changes, or are oyu over the recommended interval for changing the spark plugs?

new plugs, new coils new filter and pump, all new evap system