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[SOLVED] Number 3 Cylinder Misfire P0303 Trouble Code

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Windveil Blues

Windveil Blues

OLD FART
Hey guys,

I got the car out tonight after work and drove about 5 miles and it started missing the second I got on it (not real hard, maybe 5k). It just started missing, but no MIL yet. I got to within a mile of home and pulled over, shut it off and we sat for a minute. I started it up and took off normally, and then I saw the MIL flashing, but not steadily lit. I pulled in the garage and immediately grabbed my tuner and plugged it in to look at the trouble codes, but to my surprise, there were no codes. So I decided to go ahead and reflash it just for grins. After the reflash, I started it up and took it out on the two-lane highway we live near and went through the gears normally... nothing over 4500. I went down about a mile, turned around and hammered it. Shift light in first, melting the tires... torched them hard in second and then got out of it. As soon as I went into third, it started missing again. This time it finally threw a code: P0303. This is what AllData says:
P030x.jpg


Any ideas? It feels to me like maybe an injector. I am hoping it is something simple, as I was about to start installing cams in the damn thing tonight... but Ohhh NoooooooOoooo... there's gotta be some kinda crap that makes life interesting.

Thanks,

Jim
 
Foxman

Foxman

Well-Known Member
dead coil, Ford is know for this... pull the plug and make sure there isnt any oil in the plug well.. but most likly its the coil taking a ****!
 
Foxman

Foxman

Well-Known Member
dont drive with the ight flashing.. if you still have cats you could be buying new onces LOL... type A misfire... flashing MIL!
 
Windveil Blues

Windveil Blues

OLD FART
Well ****, Andy... I had to drive it home... you think I effed up the cat on that bank? It would be a crying shame if I had to dump the friggin' things...;) I'll go up and yank out that coil pack and get back on here in a bit.

Thanks dude,

Jim
 
Foxman

Foxman

Well-Known Member
yea dont worry about the cat... just dont drive on it for like a month like that.. I should have worded that different
 
Windveil Blues

Windveil Blues

OLD FART
Update

OK, Now I'm fairly concerned. I replaced the coil on number three with an OEM piece, started it up and let it warm to operating temp and took off down the road. It missed once or twice as I was pulling out onto the highway, but smoothed right out. I drove down to where I usually turn around (about two miles to warm the tranny up) and stood on it like I normally would, and the damn thing started missing again.

Injector? Someone told me they are certain that it's a "sticky valve." at 17,000 miles? C'mon... I know guys that launch their stock internals S197s at 5k all day on spray (Phill... LOL)!!! Whiskey Tango Foxtrot!? I have two shiney, brand new FRPP cams sitting here that cost a pretty penny, and I don't dare install them if I have some kind of pre-existing valvetrain problem.

Now for the topper... I finally got my wheels and tires today after waiting three weeks, and they sent me the wrong offset for the rears! Have I done something to piss off the Mustang Gods?? Yep, they bolted nice and tightly right up against my stock calipers... NICE.

Thanks for letting me rant,

Jim

PS Here's a couple pics of the fronts... I'm gonna have to send the rears back, I guess... Morons

new_fronts.jpg


new_fronts1.jpg
 
Foxman

Foxman

Well-Known Member
no, its not a sticky Valve.... did you change the plug or just the coil???

from the misfires from the dead coil the plug could now be wet fouled
 
02gt

02gt

Well-Known Member
Injector would be the next thing i would look at, go get the fuel sytem cleaned by profesional.... just maybe thats it.
 
wickedstangs

wickedstangs

Chula Vista, CA
Staff member
Administrator
did you disconnect the battery while doing everything? Remember you computer needs to reset.. Not the fault code....
 
Windveil Blues

Windveil Blues

OLD FART
Yep, I sure did. I also ran datalogging on everything, too. I'm sending the file to the guy who is going to do my dyno tune after I get the cams installed for grins. That is if I can get my laptop to cooperate long enough to download them from my Predator.

Jim
wickedstangs said:
did you disconnect the battery while doing everything? Remember you computer needs to reset.. Not the fault code....
Click to expand...
 
IgottaV8

IgottaV8

Wickedstangs Road Racing Team
Staff member
Moderator
Board Member
Lol, hey Emilio, can I come over this saturday to run compression tests on all of my cylinders? Maybe check my EGR Valve too if they are good.
 
Windveil Blues

Windveil Blues

OLD FART
Update

The car was driven about 30 miles today, and no misfires whatsoever. I drove it easily on the way to my destination, and easily almost all the way home. When I got about a mile from our subdivision, I pulled over to let the cars behind me go by, then I pulled back out on the highway in first and hammered it for all it was worth. Hit second as hard as I could power shifting, stayed in it all the way through third until I caught the traffic I had let go by me earlier. NO misfires... nice and smooth, not even a hiccup. I figured if it's gonna nuke, do it close to home and where I have a place to pull it over. One note I need to add here... the car had no problem at all torching those big 285 40 Nittos from a roll, either... LOL. I went and bought a set of plugs for it, but have not installed the other 7 of them yet. I just changed the plug that had been fouled by the misfire which was caused by the octane booster. Lesson learned. After I get rid of the half-tank that is in there now, I will fill up with 93 and the bottle of Techron I bought the other day. All this weather permitting, of course.

The camshaft install will take place as soon as we get a decent weekend, and I'll post up some new pics of the install, and some video as well.

Jim
 
Windveil Blues

Windveil Blues

OLD FART
Well Emilio, it turns out that octane booster is really not a smart idea. Apparently it causes plugs to foul. I won't be using anything except Techron or Seafoam in the future... and only when the fuel system needs to be cleaned. Running fine now, and I would guess it'll scream once I can get some new fuel and the Techron run through it and the plugs changed. I wanted to get all this cleared up before I even thought about installing the cams. Btw, I need to give props to Machman for his advice and help trying to figure this out... Thanks, Andy...:)
wickedstangs said:
Jim so what was the problem?
Click to expand...
 
Foxman

Foxman

Well-Known Member
I told you... when you sent me that picture of the plug and it was stained red it was from the octane booster lol... good to hear she's running good again!
 
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