MAXRB8

iTrader: (19)

Hey guys, here's my problem, I'm sure it's not fuel pump related as mine has never been touched. See Steven88's nightmare thread: http://forums.maxima.org/showthread.php?t=405560 but being a generic code P0300 it doesn't really give you anywhere specific to start! ( I have 50,00miles with Injen intake, udp and Catback). I had a serve miss under load when I bought the car (no codes) I changed the Denso Irridium plugs the previous owner had put in, I noticed the plug was almost 1/2" shorter from the lock washer to the electrode vs the factory spec NGK PFR5G-11 Laser Platinums





The car ran beautifully with just a hint of a miss on initial WOT with new factory spec plugs so I thought my problem was solved, but I discovered oil in my #5 spark plug cylinder wall. The dealer fixed that under warranty. Two weeks later I started to get the initial miss again under load. Then at WOT sever miss like I was running on 5 cylinders ( but not all the time seems more prevelant when the car has been run for 1/2 hour or so)and the SES flashed then stayed on, after a few restarts of the car and normal running around the code went away ( never read what the code was). Few days later just over a week ago at WOT SES light flashes again but stayed on this time ( same 5 cylinder feeling). Also at idle I sometimes get a popping sound from the muffler, only heard from the outside. Not wanting to be raped by the dealer I went to my mechanic's shop and he pulled the code of P0300 random miss fire, he said it only came up once ( no WOT since, and 100 miles later) but he couldn't retrieve anymore definitive info. He said only guessing possibly replacing the coils. He suggested going back to the dealer and hassling them over the #5 cylinder issue and see if they discover something else. He cleared my code last friday. Today ( Monday) the dealer says " You should have left the code in so they had something to go from", I explained what the code was "random miss fire" P0300 and there was no related info. He said they test drove it and found no miss, which I can't believe I notice it all the time depending on load and without the code they can do nothing. They said once the code comes back again which I'm sure it will under WOT to bring it in. Sorry for the length but it always helps when you have all the facts and details. Any idea's?

Menasor

iTrader: (2)

The mechanic should have left the CEL on. Normally when we get misfire codes, it'll be fouled plugs, or coils (on Direct ignition systems). The only things that I can suggest is wait for the CEL to come back on. Assuming that the coils are bad and are covered under the powertrain warranty. You should have driven with a tech to try to duplicate the problem. But maybe they told you all this over the phone. BTW, coils are a common problem on 5th gens, not so sure on 02-03 maximas. Check this thread, http://forums.maxima.org/showthread.php?t=451830 Hopefully that will help you out. Just curious, what did the dealer do to fix that issue you have with the #5 cylinder?

MAXRB8

iTrader: (19)

Thanks I had read that thread and funny I picked up my car from the dealer they found nothing and it's running beautifully ....... for now, anyway in the meantime, I've got a code reader coming and a set coils that are tested and in perfect working order, thanks to Steven88 for a great price, at least that will start the process of elmination. For those who are interested here is his thread nightmare: http://forums.maxima.org/showthread.php?t=405560

How about o2 sensors?

steven88

iTrader: (28)

Alright, let me chime in a little...

First, from my readings on the org, the coilpacks on the 2k2-2k3 don't seem to have any problems....When you look up the TSB's on studman's website, you won't see one for coilpacks that the 2k-2k1s do....also reading thru the org, there are much more coilpack threads for 95-01 than 2k2-2k3....so generally speaking, the coilpacks on vq35 seem to be sturdy...but I wouldn't be suprised if MAXRB8's were going bad...nothing is perfect in this world

I know there are two types of misfire...a lean and rich one....a LEAN misfire means less fuel and more ignition....a RICH misfire is less ignition and more fuel....both will throw off the engine and make it run

a LEAN misfire is fuel related...like clogged injectors, clogged fuel filter, dying fuel pump...etc etc...basically anything that doesn't allow sufficent fuel flow is going to be a LEAN misfire

a RICH misfire on the other hand, has to do something with the electrical system on the vehicle....the fuel is properly fed into the engine but its not getting enough spark...coilpacks, spark plugs, EGI harness (on 2k-2k1) all come into my mind immediately....

The FSM does say Primary o2 sensor as being a cause of p0300 as well....not totally sure why its related but here is my theory....Hnda_Etr has a wideband o2 sensor and he said with BOTH primary o2 sensors connected, he was running pretty lean in some areas....so lean that he caused him to misfire with a flashing SES (not sure about powerloss)....he then proceeded to try out my method of disconnecting both primary o2s and walah! His wideband o2 started reading a much more richer condition, bringing it back to stoichimetric levels and with the OBDII plugged in, no p0300 for awhile...