2000 Subaru Forester Q&A

2000 Subaru Forester Question: Engine Misfire #P0303 Please help

I detected a cylinder misfire..I have changed my spark plugs, the plugs wires looks okay to me so have not changed it yet.What could be the reason. I am also attaching my Scan result please look into it if there is any other problem that I need to consider into.. DTCs (Codes) P0303 MOD $E1 Cylinder 3 Misfire Detected ===================== State OBD Check MIL Status OFF Codes Found 0 Monitors OK 7 Monitors Inc 0 Monitors N/A 4 ===================== Record Data FRAME: -1 TM: -4.2 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 725 CALC LOAD(%) 2.4 MAF(LB/M) 0.41 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -2.3 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.115 ST FTRM12(%) -82.0 O2S11(V) 4.007 EQ RATIO11 0.999 OBD2 STAT CA --------------------- FRAME: 0 TM: 0.0 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 725 CALC LOAD(%) 2.4 MAF(LB/M) 0.42 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -2.3 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.185 ST FTRM12(%) -70.3 O2S11(V) 3.991 EQ RATIO11 0.992 OBD2 STAT CA --------------------- FRAME: 1 TM: 4.2 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 725 CALC LOAD(%) 2.4 MAF(LB/M) 0.41 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -2.3 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.085 ST FTRM12(%) -88.3 O2S11(V) 3.958 EQ RATIO11 0.990 OBD2 STAT CA --------------------- FRAME: 2 TM: 8.4 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 738 CALC LOAD(%) 2.4 MAF(LB/M) 0.42 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -3.1 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.110 ST FTRM12(%) -82.0 O2S11(V) 3.969 EQ RATIO11 0.991 OBD2 STAT CA --------------------- FRAME: 3 TM: 12.6 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 738 CALC LOAD(%) 2.4 MAF(LB/M) 0.42 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -3.1 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.140 ST FTRM12(%) -84.4 O2S11(V) 3.974 EQ RATIO11 0.998 OBD2 STAT CA --------------------- FRAME: 4 TM: 16.9 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 725 CALC LOAD(%) 2.4 MAF(LB/M) 0.41 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -3.1 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.075 ST FTRM12(%) -88.3 O2S11(V) 4.013 EQ RATIO11 1.002 OBD2 STAT CA --------------------- FRAME: 5 TM: 21.1 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 725 CALC LOAD(%) 2.4 MAF(LB/M) 0.78 MAP("HG) 17.4 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -2.3 LT FTRM1(%) -1.6 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.750 ST FTRM12(%) 8.6 O2S11(V) 3.797 EQ RATIO11 0.987 OBD2 STAT CA --------------------- FRAME: 6 TM: 25.3 MIL STATUS Off ABSLT TPS(%) 12.9 ENG SPEED(RPM) 1188 CALC LOAD(%) 4.7 MAF(LB/M) 0.62 MAP("HG) 5.9 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -0.8 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.780 ST FTRM12(%) 21.9 O2S11(V) 4.001 EQ RATIO11 1.007 OBD2 STAT CA --------------------- FRAME: 7 TM: 29.5 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 750 CALC LOAD(%) 2.4 MAF(LB/M) 0.41 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -1.6 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.740 ST FTRM12(%) 15.6 O2S11(V) 3.938 EQ RATIO11 0.988 OBD2 STAT CA --------------------- FRAME: 8 TM: 33.7 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 738 CALC LOAD(%) 2.4 MAF(LB/M) 0.41 MAP("HG) 9.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -3.1 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.740 ST FTRM12(%) 15.6 O2S11(V) 3.956 EQ RATIO11 0.994 OBD2 STAT CA --------------------- FRAME: 9 TM: 37.9 MIL STATUS Off ABSLT TPS(%) 1.6 ENG SPEED(RPM) 1200 CALC LOAD(%) 3.1 MAF(LB/M) 0.70 MAP("HG) 11.2 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 31.0 ST FTRM1(%) -2.3 LT FTRM1(%) -0.8 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.035 ST FTRM12(%) -95.3 O2S11(V) 3.913 EQ RATIO11 1.126 OBD2 STAT CA --------------------- FRAME: 10 TM: 42.1 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 950 CALC LOAD(%) 2.7 MAF(LB/M) 0.45 MAP("HG) 8.6 COOLANT(°F) 244 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) 0.0 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 OPEN1 FUEL SYS 2 OPEN1 O2S12(V) 0.195 ST FTRM12(%) -64.1 O2S11(V) 3.943 EQ RATIO11 0.991 OBD2 STAT CA --------------------- FRAME: 11 TM: 46.4 MIL STATUS Off ABSLT TPS(%) 0.0 ENG SPEED(RPM) 725 CALC LOAD(%) 2.4 MAF(LB/M) 0.41 MAP("HG) 9.2 COOLANT(°F) 241 IAT(°F) 129 IGN ADV(°) 15.0 ST FTRM1(%) -3.1 LT FTRM1(%) 2.3 VEH SPEED(MPH) 0 FUEL SYS 1 CLSD FUEL SYS 2 CLSD O2S12(V) 0.780 ST FTRM12(%) 21.9 O2S11(V) 3.907 EQ RATIO11 0.978 OBD2 STAT CA ===================== View Freeze Data P0303 (MOD $E1) TROUB CODE P0303 ENG SPEED(RPM) 2438 CALC LOAD(%) 33.3 MAP("HG) 28.3 COOLANT(°F) 210 ST FTRM1(%) 0.0 LT FTRM1(%) 2.3 VEH SPEED(MPH) 31 FUEL SYS 1 OPEN1 FUEL SYS 2 N/A -
Answer 1
You need to check the sparkplug wires with a meter and also that #3 wire is not leaking to ground. Appearance has little to do with performance. You could also check the injector for resistance (probably about 15 to 20 Ohms) and a "click" noise if you put power and ground to the terminals. you may need to check compression. One thing I notice in your 'Frame' data is that the engine is overheated, running at 244F! I don't know what to make of that but that in itself demands attention. You didn't say what the mileage is but if it's been running that hot you could have a bad head gasket or other problems contributing to the misfire. Here's a directory link for you: http://repairpal.com/directory?address=94536&car_brand_names=Subaru -
Comment 1
Thanks SuperBob, You are right, unfortunately the #3 wire appeared to be the culprit. I have changed all the 4 plug wires and the engine no more misfires. I am little concerned on overheated engine which showed up as 244F, I have already logged 165000 miles on my car. Does that indicate that i need to flush my antifreeze to restore normal values. What should be normal values anyways. -
Answer 2
THANKS FOR YOUR QUESTION, I HAVE FOUND SEVERAL RESONS FOR #3 MISFIRE, PLUG WIRE, BUT WHEN WIRE IS BAD YOU NORMALLY FIND PLUG IS SOILED. COULD HAVE A BAD INJECTOR,COULD HAVE A BAD COIL. NEED TO CHECK ALL WITH THE APROPRIATE ANOLIZER TO DETERMINE THE PROBLEM -