PCM Code 300 - Engine Misfire - What should I do?
Thread Starter
Safety Car
Joined: Jun 2000
Posts: 4,247
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Cruise-In II Veteran
PCM Code 300 - Engine Misfire - What should I do?
Please look at my mods in my sig. Specifically the Superchips Micro Tuner 2000. Should I try to diagnose the problem myself or should I just take it to the dealer. If I'm going to take it to the dealer, how many of the mods should I remove? This is a list of easily removed mods. Would I be better off leaving the mods on and facing the possibility of not having the fix covered under warranty? At least the fix would incorporate the mods I plan to keep.
Superchips Micro Tuner 2000.
Ported MAF Ends
Donaldson LS6
Relocated MAT Sensor
Thanks,
Jim
Superchips Micro Tuner 2000.
Ported MAF Ends
Donaldson LS6
Relocated MAT Sensor
Thanks,
Jim
Former Vendor
Joined: Apr 2001
Posts: 10,976
Likes: 21
From: FL
St. Jude Donor '13
Re: PCM Code 300 - Engine Misfire - What should I do? (EvilDeed)
Before you do any thing,remove the fuel rail covers and inspect (real closely) the left and right injector harnesses (wraped in black tape) for a short to ground.This commonly causes the P0300 code.I have seen on about 5 occassions were the #5 injector harness rubs on the razor sharp fuel line retaining clip were the braided fuel line connects to the fuel rail.This applies to 2000-2001 only.Also,look were the injector harness wraps around the back of the rocker cover.You will see a bracket were the harness rubs on.Also,make sure that the spark plug boots are fully inserted.
If you cant find the fault,the dealer can check missfire history with the Tech 2 to isolate exacatly which cylinder is missfiring.This eliminates alot of guess work.
As a far as the mods,it all depends on who the judge is :smash: ...
If you cant find the fault,the dealer can check missfire history with the Tech 2 to isolate exacatly which cylinder is missfiring.This eliminates alot of guess work.
As a far as the mods,it all depends on who the judge is :smash: ...
Thread Starter
Safety Car
Joined: Jun 2000
Posts: 4,247
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Cruise-In II Veteran
Re: PCM Code 300 - Engine Misfire - What should I do? (C-5 TECH)
Thanks C-5-Tech. Going to check it out right now. That would make sense. When I had the headers installed, they were working in there quite a bit.
Jim
Jim
Thread Starter
Safety Car
Joined: Jun 2000
Posts: 4,247
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Cruise-In II Veteran
Re: PCM Code 300 - Engine Misfire - What should I do? (C-5 TECH)
Oh my. Combine paranoia with idiocy and you have me. I'm threatened by all this new computer controlled stuff so much that I think past the simple. I'm very embarrassed to say that not one, but two of my plug wires were almost falling off. I hate to even consider the notion that they have been off for some time. The last time anyone was under my hood was about 1500 miles ago when I had the headers installed. BTW, those wires don't seat on the plugs very firmly, do they?
Oh well. I hope that fixes the problem.
Should I be concerned about any damage to the plugs or wires if they were loose for an extended period of time?
Jim
Oh well. I hope that fixes the problem.
Should I be concerned about any damage to the plugs or wires if they were loose for an extended period of time?
Jim
Le Mans Master
Joined: Jan 2001
Posts: 5,564
Likes: 1
From: San Leandro California
Re: PCM Code 300 - Engine Misfire - What should I do? (EvilDeed)
I shouldn't think that there would be any damage by that.
I had the same problem when I installed the 440-6 Pack on my 'Cuda. I didn't make sure that one of the wires had "clicked" when connecting it to the plug.
I had the same problem when I installed the 440-6 Pack on my 'Cuda. I didn't make sure that one of the wires had "clicked" when connecting it to the plug.
Burning Brakes
Joined: Apr 1999
Posts: 1,150
Likes: 0
From: Saratoga CA
Re: PCM Code 300 - Engine Misfire - What should I do? (C-5 TECH)
If you cant find the fault,the dealer can check missfire history with the Tech 2 to isolate exacatly which cylinder is missfiring.This eliminates alot of guess work.
Thanks,
99 C5 M6
