I’m losing my mind over P0300-6 codes on my 96. 300 is random multi-cylinder misfire, then 301-306 are the individual cylinders.

I used to throw a code maybe once a month, I’d clear it, and it’d go away. After replacing the injectors with rebuilt Bosch 12 hole, it ran better and stopped throwing codes, that was in July. About a month ago it started throwing a code again, and recently more frequently, now about once a day driving about 15 miles.

In the last 6 months I’ve replaced:
Injectors
Fuel filter
Plugs
Wires (Taylor)
Coil (Mopar)
Cam sensor in dizzy
Cap/Rotor (Accel, then WVE just to try something else)
IAC
Crank Position Sensor
Probably more

I’ve checked fuel pressure, I’m right around 50 psi at idle. Anybody ever have intermittent fuel pump issues? Could that be it?

Most recently I did the CPS, thought it was fixed because I didn’t get a code for 2 days, then bam, CEL back on today. Erg!

The codes I get the most is 0300 and 0305. I guess I need to do a compression check on #5, but I doubt it is low since it generally runs great.

Not sure what to change next. I’m getting a little tired of throwing parts at it and clearing the codes every day. I have a code reader, not a scanner.

 

Have you replaced the o2 sensor yet? That can cause the p0300 to happen if its bad.

 

It could also be the harness/connectors to the PCM, they ground the spark, try unplugging, clean PCM connectors with spray electolube

clean main earth stud x 2 on engine block

 

Start on p. 328:

http://sturescykelverksta.com/dodge/...n_sgmldiag.pdf

If you still can't find anything we need to get a Hantek.

 

Did the downstream one about a year ago. I could try the upstream one... Thanks

Will do!

Whoa. Thanks!

 

Downstream one does virtually nothing. Upstream one is the important one.

 

I'm on it

 

Exactly. The downstream one on a 96 does nothing but tell the PCM when the CAT needs to be replaced. It has NO effect on the engine. None. Zero. Zip. Zilch. Nada.

 

That was it.

Always an adventure getting these things out when they are original... but that seems to have been it. I've driven around for about a week without any new codes. Thanks all for the help!

 

Did you get this jolt issues sorted. I am having same issue at 70km with low idle.