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?
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?