chad99evo

iTrader: (24)

ok, kevins out of town and my car is throwing a P0303 code:

this is cylinder 3 misfire.

heres possible causes:
-Faulty spark plug or wire not this
-Faulty coil (pack) not this
-Faulty (front) oxygen sensor
-Faulty fuel injector
-Burned exhaust valve
-Faulty catalytic converter lol not this either
-Running out of fuelnot this
-Poor compression not this
-Defective computer not this

so ive been down this list of things, checked and swapped good parts from other evos(thanks Young & Jon Bisios, appreciate the help), data logged, everything is good, except that damn misfire which is a real PITA. know im getting significant fuel pressure or it wouldnt run like it does at WOT, tune is good has not and will not be altered(common sense), a little rich but a safe tune nontheless, no vacuum leaks or boost leaks.

heres where i am now:
-Kevin mentioned the o2 sensor(the one that matters, by the turbo ) caused a problem before he left town, but the code hasn't been on for it anymore, BUT according to my readings on EvoM this could lead to the p0303 misfire and crap running conditions nontheless. I'd like to try this option first.

-faulty injectors, these are brand new 1200cc precision injectors and checked where they plug in and theyre all good, but IF somebody has an extra 1200 lying around which i could swap that would be good to see if it solves the problem. last thing i want to check because kind of a PITA to change out

-and last but not least, burnt exhaust valve: not going that far. that would be something i could screw up and should leave to denver/kevin, they are the smart guys that know about that stuff.

Basically, Ive narrowed down the plugnplay things that i can do to not void my KevinD warranty lol. Heres what i could use in this order:

1. somebody to meet me with their car, and we can swap front o2 sensors to see if that does the trick. in fact, it makes the most sense to me that this is the cause of the problem after reading what i have read. if so, you get your sensor back and i go buy a new one. everybody's happy

2. same as above, but with a 1200cc injector(lol its hard to find people with 1200's)

and last, but most important,

3. i wait till kevin gets back if none of these fix the issue, and let him do the big boy stuff so i dont screw anything up or fubar my warranty with him.

chad99evo

iTrader: (24)

I think AndrewZaragoza is coming in the AM (guess thats today, im up kind of up late) and will probably try the o2 sensor swap. any and everybody feel free to chime in with advice and willingness to help LOL. I will let yall know what happens if this 02 sensor thing fixes it(fingers crossed).

otherwise ill be doing more even whining, nagging, and *****ing(apparently i wasnt always like this, the ex somehow used her evil thailand powers to make me more insane)

andrewzaragoza

iTrader: (6)

lol. i wasn't able to go to u this morning since i woke-up late. for the injector you could switch it from another cylinder like swap 2 & 3 if the code moves to the 2nd cylinder (p0302) then its the injector. as for the o2 sensor i suggest borrowing from someone who has an extra since its a bit of a pita to remove one.

chad99evo

iTrader: (24)

the injectors are more of a pita to remove because of fuel and the fuel rail has to come off. all you have to do for the o2 sensor is unscrew and plug in. anybody else?

nikkadanny

iTrader: (31)

taking off the front o2 sensor off of a stock turbo set up is a B..........ch

codymac

I'd move the injectors around before touching the O2 sensor.

Easier to get to to, easier to swap, and doesn't require anyone else (to provide parts or help). If the misfire follows the injector, the cause is a no-brainer - if it doesn't, there's no reason to pull it back apart (like with a loaner injector from someone else).

And... if the injectors are new to the car.

The real question is what was the issue with the O2 sensor? Clarifying that might make it seem like it's a more likely culprit.

eta: If it were the O2 sensor, would the misfire not happen on other cylinders as well?

666 EVO

iTrader: (37)

You can check the plugs to see if a injector is having problems. They should all be burning the same. If one is covered in fuel, dark or light than the others then that will be your injector that is having problems.

chad99evo

iTrader: (24)

New decision. wait for denver or kevind. problem will be solved there. lol. thats the smart thing to do.

Justin Tyme

I will agree with others, you shoudl swap the injector out with another. ITs easy and doesnt require anyone else to help. Looking at the plugs will give you a good idea of what is going on though. That is the first thing I would do. If #3 looks light, dark, or covered in fuel it gives you an idea of what is going on and tells you the problem lies in just the #3 combustion chamber. If all of them look the same but you are still getting the code then I would suspect the O2.