2G P0303 misfire code

[Turbolence56]

Hey guys, having some issues lately with my gsx. 97 gsx with 6 bolt swap. 1000cc injectors, ecm link, Ngk w turbo and fp manifold, fmic etc.

so car was running well as of late, however several days ago a random code p0303 code came up. I cleared it and it went away for a few days. Car was sputtering only in the 3k-4K range. Fast forward a few days and it is coming in every time I start the car and now car runs like it’s on 3 cylinders. Sounds like a wrx. Car idles fine, no smoke, just doesn’t have any power and can barely get up to 80mph.

barely got to work today. What could it be, fouled spark plugs? Bad ignition wires, clogged injector? Bad coil pack?

I need some help, I searched the forums and found some ideas, so going to start with the simple stuff like new spark plugs.

Im currently daily driving this car so it needs to at least get me to and from work . Could spark plugs go bad in just one cylinder? Same for ignition wires? Can just one go bad?

many help would be appreciated! Thanks as always awesome forum.

 

[Widgmaster]

You are correct in assuming that one plug or one wire can go bad. I have read in many posts that Autozone or O`Riles will scan your car for coeds for free.
Read this article.... https://www.autocodes.com/p0303_mitsubishi.html

 

[Turbolence56]

I scanned the codes already, cleared the p0303 code but still runs like ass. I have NGK wires, no other codes. Plan to change out the spark plugs and wires and check the coils.

 

[Widgmaster]

That article I posted said it's your 3rd cylinder is the problem. Removing the code does not correct the issue... Replacing just one spark plug in that cylinder sound stupid to me, but I see you said you are going to replace them all. Smart man

 

[Turbolence56]

Yeah, I’m planning on replacing all of them. I was just asking if only one spark plug could foul, or just one wire could fail….
Ngk 6s or 7s for my spark plug set up. 15 psi on fp 68HTA

I know clearing the code won’t fix the issue. I just hope it is not something worse. But plugs and wires are cheap so go the easy route first.

my questions now is, I have a 6 bolt swap bought that way. Do I need 1g wires and spark plugs or 2g.

 

[AWD-Tony]

Post a log

 

[Widgmaster]

That I can not answer my friend… I will leave that to someone with more knowledge than myself… But I'm curious to know why the different 6 or 7 bolts would have any bearing on the plugs? I'm just learning myself so if someone out there has the answer to my question please reply

 

[pauleyman]

Yeah, I’m planning on replacing all of them. I was just asking if only one spark plug could foul, or just one wire could fail….
Ngk 6s or 7s for my spark plug set up. 15 psi on fp 68HTA

I know clearing the code won’t fix the issue. I just hope it is not something worse. But plugs and wires are cheap so go the easy route first.

my questions now is, I have a 6 bolt swap bought that way. Do I need 1g wires and spark plugs or 2g.

That depends only on the location of the coil pack. 1g and 2g are different. The only difference is the length of the wires. Do you know what all 1g parts were used? If you're not sure post a pic.

 

[Turbolence56]

I’m at work currently so can’t post a log off ecm link. Not the greatest picture. Will get a better one later. Not even sure you can view anything.

so length of the wires is the only difference, from 1g to 2g?

also what’s the odds it’s a fuel injector problem? Like clogged injector I’m running some fairly new in the last year or so of some 1000cc injectors. New fuel filter, always run 93 octane gas.

I’m leaning towards spark plugs and wires as I don’t know the age of them. But it could also be coil related. But wouldn’t I see 2 cylinders bad, since 1 coil pack goes to two cylinders? Or am I wrong in this?

appreciating the help guys thank you so much.

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[pauleyman]

That is a 1g setup. If you have a physical problem with a coil tower, plug or wire you could drop only one cylinder. You are correct you would usually drop two cylinders with a coil but something like a cracked tower etc would only cause one. You can sometimes find tiny burn marks on the plug wire boot indicative of a misfire. Looks like a small white dot. From past experience it's worse under load/boost.

 

[Turbolence56]

Yeah car stinks under load and boost. But idles ok l, but you can here it misfiring even at idle. I’ve also had a loud ticking sound coming from that area. It’s pretty loud could it be arcing? The car is almost in drivable at this point. The sputtering and misfire has gotten progressively worse over the last few days. Hopefully can diagnose it soon. Will look at the wires and coil pack shortly and report back

 

[Turbolence56]

Car does run ok ish under partial throttle though. But as soon as you get over 3500 or into boost it gets worse. For info not sure if this is related, but I did remove my battery and alternator as I thought they were bad. They are ok and I put them back in. Had a loose positive battery cable clamp (now fixed). Thanks for the help though. So if I find anything I should buy 1g ignition componets? Wires, and / or coil packs?

 

[pauleyman]

Yeah car stinks under load and boost. But idles ok l, but you can here it misfiring even at idle. I’ve also had a loud ticking sound coming from that area. It’s pretty loud could it be arcing? The car is almost in drivable at this point. The sputtering and misfire has gotten progressively worse over the last few days. Hopefully can diagnose it soon. Will look at the wires and coil pack shortly and report back

Takes a minute to pull wires. Look at them.
Yes this could be arcing.

 

[AWD-Tony]

You can swap wires and plugs to different cylinders and do a cylinder drop test to see if the misfire follows a wire or plug.

 

[Turbolence56]

I fixed it. Ended up being that the number 3 wire was not seated all the way down in the spark plug well. However having a new issue now, leaking power steering fluid