Random Multiple Cylinder Misfire
 

My car is throwing a "Random multiple cylinder misfire code". I will be driving (usually on the highway) between 60-80 mph and the car will misfire, then the light comes on. It feels like a shudder or like you are driving over rumble strips, just as described in other posts. It will not stop shuddering or accelerate unless you release the gas pedal. It will happen for a few days, then the code will turn itself off and it won't happen for a week or two. Then, the cycle repeats.

I have been reading these posts for a few days and people keep saying it is related to the tranny. I had a John Shepherd stage two tranny and a street clutch put in. This is not a rebuild or anything. It was a BRAND new Shepherd transmission, so i would think that it wouldn't be a tranny problem. I have changed and checked my spark plugs and coils.

Could it be a sensor?? I have taken it to two shops and they cannot figure it out. :crap:

**I have a 2003 Evo with 100,000K

i had the same problem when i was going over 70 on the highway, light came on, i just use my scan tool and erased never came back, its a TSB on alldata about that

I have erased it many times, and it still comes back. It's tormenting me.

im pretty sure it could be coils my man, cuz i had that problem befor, so i change spark plugs ,coils and wires,,hop dat helps u

I had that same problem, it was blow out when cold.

I had my plugs gapped at .25 , I had to go down to .21

It feels like fuel cut off.

Common aka normal problem for the 03 to throw the p0300 code. Just get it disable, keep searching and you will find all kinds of threads about it. G/l

+1 Sounds like bad coils, I've had a few bad ones and the car acted like that... If you have a friend with an evo just swap coils and test :)

My 06 had this CEL after the dealer replaced axle seals, and the tech OBVIOUSLY ripped on it. Tellin me how strong it pulled etc.. douche bags. I cleared it, if it comes on again Ill by COP that day, until then COP is in the future.

Its likely not a bad coil/s. Search P0300 code on here more info then you can read in a month dating back to 03.

I certainly wouldn't just go buy a COP thinking this was your fix cause just swapping in a COP may not do squat for the issue. I'd look to cam/tuning, plug gap, coil testing first.

Set box 4 and 5 in periphery 2 to 0 it will disable the p0300 test ... fixed my problem and many others.... :)

^ this is what I did and never looked back or had a problem again!!

Disabling it will stop the random misfire code, but you would still feel the effect of the misfire if it was happening. A bad wire can cause this issue.

By disabling the code you 100% will NEVER have this scenario as quoted by the OP ever again in regard to the P0300 code

"It feels like a shudder or like you are driving over rumble strips, just as described in other posts. It will not stop shuddering or accelerate unless you release the gas pedal"