Hello,
97 Avenger 2.0L, 70k miles

My daughters car started misfiring all of a sudden. It is intermittant. I checked the fuel pressure and it was 51psi. (it was pulsing quickly between 49 and 52....is it normal for it to pulse like that?) I checked the pressure while it was misfiring, so I don't think it's the fuel filter. I ohmed out the coil and the spark plug wires and they look good, spark plugs look good. Also getting code P0300, P301

Is there a common failure with this, or do I need to go thru all the fuel, air and sensor components?
Thanks...

 

Hello Mark and welcome to DF.
300 is multiple misfiring detected
301 is cylinder 1 misfiring
Have you check the plug gaps? Possibley the camshaft position sensor (CPS [look for CMP in the book]) is going bad. The CPS is a common issue in the V6.
When was the last time your daughter's car had a tune up by chance? I understand that you checked the plugs and wires, but if they're old, they're old

 

Hello,
Thanks for repling.

Ok, I'll try changing the plugs and wires and checking the crank sensor.

 

I was gettting the same codes as you were, the multiple cylinder misfire was due to oil in the sparks. P0301 however I am still trying to figure out- plugs, wires, cap, rotor and distributor has been replaced. The car runs smooth and accelerates decent for what it is but I still get that misfire at idle. I would suggest you also check the injector while you have it open.

 

Hey Slice, your CPS could be bad or going bad. The CPS tells what plug to fire and when to fire...so to speak that is

 

The Haynes manual says the Camshaft Position Sensor (CMP) is in the distributor, and must be replaced with the distributor, while the Crankshaft Position Sensor (CKP) is located right under the distributor and can be replaced.

Would that really cause only one cylinder to misfire though? Especially when cold?

 

Good info thanks. I'll let you know what I find. As soon as my daughter gets off her *** and does some yardwork for me I'll look at the car again....lol.

 

Honestly, it could also be plug gapping, condition of the plugs, too much fuel (o2 sensors), not enough fuel (o2 sensors), condition of the motor, etc. The CPS is just a common issue.
You're also correct about the crankshaft pos. sensor and that is the one that is the usual suspect. The one in the distributor is a rare, but it can happen, issue.

 

Well, it's fixed!!
I wouldn't have believed it if Ihadn'tseenit myself, but it was the spark plugs. One of the plugs measured 25ohms from the top to the bottom center conductor and the others allread 20ohms. I guess maybe they were all justplumb tuckered out. Sure seemed like a deeper problem from the symptoms. At least I got my daughter to pressure wash the patio.

 

Good deal Mark, too bad you didn't get your daughter to do some yard work other than the patio, lol.
Just kidding, you did good, that's what dad's are for right?