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P302 code everyone is getting.


What was your misfire code caused by?  

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  1. 1. What was your misfire code caused by?



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Just started getting a P302 cylinder misfire. It just began when it started getting colder out so not sure if that plays in. Had it tuned to stage 1 in the spring so I was worried it might be having trouble with the colder charge. But anyways I figured it could have been bad gas maybe? So I put in Techron fuel injector cleaner and some BP 93 octane at a half tank hoping it would clear it up. I have about 20 miles on that tank so far, reset the light after the 20 miles and left it over night. Came back and drove to work and it came on again.

 

So now Im thinking either plugs (which have not been changed since I purchased it 9k miles ago. Its now at 77k miles.) or hopefully not but it could be injector or coil I understand.

 

-I guess my questions are, where do you get the stock plugs cheapest? ( I have have found them for 50 for 4 online not including shipping)

And I know the colder plug thing is all over the place but was wondering to save 20 bucks would it be okay to go one step colder with generic NGK? I do live somewhere cold, I heard the generic have to be gapped from .40-.44 to .28-.32 which would be a pain, and I do not want to loose MPG.

 

-Can I just switch the two front cylinders coil packs to see if the code moves? So #2 to whatever is across from that. Would it cause any problems?

 

-If the code stays after plugs and coil is switched I assume injector, so I have heard you can switch them as well but I could not find a writeup on doing that in searching and Im just wondering if someone has a link.

 

Thanks.

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You can swap coils, and you can check the plugs. Both are good ideas.

 

But check also for manifold gasket leaks - as stated in other threads. The donut gaskets are right now the common theme for this and similar kinds of behavior.

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Well it looks like first step before spending money is to switch the injector from the bad cylinder with another cylinder as this is the easiest.

 

Then if it moves replace the injector, if it does not now you switch the coil pack the same way. At this point you could do the plugs too if you wish as the coil could be a pain. For me I have 302 so I will try the pack before plugs as it looks like #1 and #2 are not to bad to switch.

 

If it moves now, replace the bad coil.

 

If its still the same cylinder you would want to try injector cleaner or the Subaru dealers Terrasomething to clean the valves. Also clean the maf and map.

 

If it does not move try plugs and check the wires. Couldn't hurt to do the plugs now anyways unless you just did them.

 

Then apparently check your exhaust gaskets, for leaks. As well as get some carb cleaner and spray around different hoses in the engine bay to see if the engine revs. If so it means it sucked in some carb cleaner into the leak and it would be a hose in that location and should be replaced.

 

At this point you would likely want to take it to the shop, or start pulling apart the engine.

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shop. labor for head removal/install, new timing belt/water pump install, replacing all gaskets, clutch install and installing the killer B oil pickup is about 1000, machine shop is about 800. machine shop includes parts (valve guides and a valve) all other parts are mine.

car needs a clutch and now is the time to do it, exedy kit with lwfw on amazon for 450 shipped.

 

not happy to spend this kind of cash for a car with 55k miles on it.

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if this problem only started when the engine was fully cold and the outside temp was cold, and the problem subsides once the engine is fully warmed- thenit's the intake manifold o-ring gaskets. when it runs rough before the engine is fully warmed, there is a presence of a vac leak and causes misfires/lean condition which can throw a CEL. The CEL will stay on until cleared. It may not be misfiring once warm but the light will stay on. So it would be good to isolate the conditions in which the misfires occur.
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Hmm it does seem to happen (and start) when it got cold out. Although it seems to happen even if the car is warm and mostly at low rpm. Only reset the cold three times so far so havent been able to link when it happens besides at low rpm. Will look into this more.
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I never got the code number thrown, but I bought my car in winter and it came from Florida. The second day I was driving it it threw a CEL and started stuttering and nearly dying.

It was the intake manifold gasket shown as a misfire CEL.

I suspect it was sold to me that way because the dealer hadn't tested it long enough (been on the lot for only a few days) and the car, being from South Florida, had never seen a cold day before and the gasket hadn't had a chance to shrink enough to throw the code.

So I'd start there and work inward.

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Well swapped the injector, no luck. So Just went to the dealer and wheeled and dealed until they gave me the plugs for the same price as autozone 60 bucks for all 4 taxes not included, they just had them in stock. So now to swap coils and change plugs.

 

If that does not work I guess the next thing would be to either take off the intake / exhaust and check gaskets or would you think it would be better to just pay for a compression test at this point? Deal quoted me 150 bucks for the test. Is that higher than you can find normally?

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But plugs are much less than $60 at the dealer. :lol::confused:

http://Www.fredbeans.com

 

I think you mean Fredbeanparts

 

http://www.fredbeansparts.com

 

All I could find on there are the aftermarket one step colder plugs. To find the OE plugs it seems like the cheapest even on ebay and amazon are 10 bucks a plug then 7 bucks shipping.

 

I do not want the non OE plugs because from what I understand is the OE plugs have the correct index as well as are gapped to .28/.30 where as many of the other NGK come as .40 and have to be gapped. Also I live in MN where it gets to -20 sometimes in the winter and I want to be able to start my car haha.

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