What failures can cause a misfire code? If the Opti-Spark, wires and plugs are replaced and the code re-appears, what should be checked next?

Thanks very much.

 

What is the code being set? Then we can tell you

 

The code was P0300 - misfire. Thanks for any information you can provide.

 

Are you running an aftermarket cam? If you get a little on the wild side with overlap, the crank sensor irregularities will set the misfire code.

But, in general, anything that can cause a random misfire will set the code.... ignition problems, fuel problems, leaking EGR valve, etc.

 

From my experince the PO300 code is a "false code" in the sense of there being nothing wrong. If you have an aftermarket cam, like Fred says the crank postion sensor goes nuts from some reason and will throw a code. I had one for the better part of a year with no problems or loss of performance.

Check everying out to make sure, and from that point on just ignore the light.

 

i just got the same code after the rebuilt of my 355.. it ran find for 500 miles, then @about 580 miles, the 0300 code came on, and i've been having problems figuring this out..the opti is good, cause i just changed it during the rebuild, the plugs and wires are good.. no vaccum leaks.. as far as the plugs are, #7 plug was a little wet when i pulled it out.. i've been getting many opinions that the programming is making the car too rich and dumping in too much fuel.. i've done a search on this and it's been mixed remedies as to how this can be corrected.. the scan tool says my #2 and #7 are misfiring.. you can feel it through the car.. i had my computer tuned by PCM4Less, but i've been having troubles getting in touch with them... i have an appointment set for Cartek to dyno tune the car.. hopefully that'll solve the problem.. any opinions???

thanks
vinnnie