Mechanics

I HAVE A 3.9L. OBDII SAYS THE CODE IS A P0301 (MISFIRE #1 CYLINDER) HOW DO I FIX THE PROBLEM?

2002 Dodge Dakota • 111,000 miles

I have a 2002 dodge Dakota 3.9L. I was recently driving home one night and the check engine light came on (it stays on and does not blink)when I got home I hooked the truck up to the OBD II and I received a P0301 (#1 cylinder misfire). I tried replacing the Plugs, Wires, Distributor cap, Rotor, ignition coil, drive belt and the air filter and rest the code about 50 miles later the light came back on. I switched the #3 fuel injector with the #1 to see if it was bad (it wasn't). I also checked the wires to the injectors to make sure they are getting power and they were. I checked the pressure coming from the fuel rail and it was at 49 PSI. I did a compression check and here are the results 1. 155 PSI, 3. 167 PSI, 5. 166 PSI, 2. 164 PSI, 4. 155 PSI, 6. 169 PSI. I checked the vacuum pressure from the booster lines and set the idle to 2000 RPM (a smooth idle). The pressure was at 50 PSI with a tiny bounce in the needle and the gauge said it was a normal motor. Nothing has worked so far. Any suggestions?
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Dkdennis0702
July 12, 2012.




I recommend you check and test the crankshaft positioning sensor or replace it as you wish -start here and let me know

Rasmataz
Jul 12, 2012.
Rasmataz, I tried the crankshaft sensor drove it 20 miles and the light came back on.
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Tiny
Dkdennis0702
Jul 17, 2012.
Rasmatz,

I had the truck hooked up to a computer and it said that cylinder #1 was not the problem and that it was actually cylinder #4 that had the miss. I guess 1 and 4 fire together. It also said that bank 2 (passenger Side) was running lean at idle but was ok while driving. Any advice?

Tiny
Dkdennis0702
Jul 30, 2012.
Check both no.1/4 injector resistances

Rasmataz
Jul 31, 2012.

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