Ford Mustang 2004 V6 3.8L OBD codes P0461 P0316 P0303

Maintenance/Repairs
1

Hello broke college student here that would rather learn how to fix a car than take it in.

odometer: ~135000

04 convertible mustang V6 showed p0461 OBD code initially just causing the gas gauge to fall to empty only on the last quarter tank. I just filled up at that point and left it.

P0316 and P0303 showed up after i experienced a loss in power and rough idle. I replaced the spark plugs, wires and even the coil pack. Problem came back so i replaced the MAF sensor. and it came back again. I then replaced my fuel injectors and the car ran fine for about 200 miles before the problem came back and almost worse. Complete loss of power when going uphill its embarrassing (barely pushing 20 mph when flooring it) and some loss of power when accelerating on the freeway. There is definitely hesitation and jerking when driving at some higher speeds and the car changes gear.

After some research im guessing it could be the fuel pump/sending unit or FRP sensor. I am trying to save money so any recommendations would be great on how to diagnose or what the issue might be.

2

Many directions can be taken, but seeing that the missfire seems to be isolated to #3 cylinder, you might want to start over with your diagnosis technique. Even though parts are new, swap #3 plug with another plug and see if code switches to another cylinder. If it does replace bad plug if it doesn’t swap #3 wire with another wire. If code moves away from #3 replace wire. Do the same technique with fuel injector. If all this doesn’t do anything, you need to check your fuel pressure. If that’s good you need to check for vacuum leaks. That ought to keep you busy for a little while. Please let us know your progress.

3

Dirty fuel filter?

4

Taken together, a P0461 and a P0316 tells me there is a fuel delivery problem. The P0416 says it may be electrical that caused inadequate fuel to feed the engine upon startup.

Pull the pump, check the wiring carefully, especially grounds. I’m thinking dirty ground.