For the past few weeks I've had my CEL coming on/going off.. it's usually off for about the amount of time that it's on. Anyway, It is always cylinder 3 and 4 misfire, sometimes 1. I replaced all of the plugs and cyl 3 coilpack--the issue persists. The car doesn't seem to be losing much power (if any). It's just as slow as it was when I bought it as far as I can tell.

Here's the freezeframe data I just got from the scanner... I'm hoping someone can help!

DTC that cause freeze frame - P0303
Throttle Position - 9.4%
Engine RPM - 729
Load Value - 28.6%
MAP Sensor - 29kpa
Coolant Temp - 181 Deg F
Intake air temp - 86 Deg F
Short term fuel trim 1 - 1.5%
Long term fuel trim 1 - 3.1%
Short term fuel trim 3 - -100.6%
Long term fuel trim 3 - -100.6%
Vehicle speed - 0mph
Fuel System 1 - CLSD
Fuel System 2 - N/A

I don't really know anything about fuel trim, as far as what it is supposed to be. This is just the data I got from the scanner.

Any help is appreciated!

 

note that your long and short term fuel trim is pinned at -100% meaning that the the car is trying to pull back fuel injection. looks like your fuel injector might be leaking...

ideally, your long term fuel trim should be at 0%.

used injectors can be purchased for pretty cheap...if you want, google how to clean them...

 

How many miles are on the car?


Check the fuel pressure. It should be 270 - 320 kPa (2.8 - 3.3 kgf/cm², 40 - 70 psi)

Also check the valve clearances. Intake: .18 - .22mm (.007 - .009 in.) Exhaust: .23 - .27mm (.009 - .011 in.)

 

Is it safe to assume that 'fuel trim 1' refers to cylinder 1 and 'fuel trim 3' refers to cylinder 3? If that's the case, I should be paying most of my attention to the #3 injector?

180k miles on the car. I'll see about checking those two things. Thanks!