threw a 302 misfire code...?

[000104Mustang]

Everyone,
I own an '04 GT that recently threw a 302 misfire code. I live in AZ and took it to All Mustang Performance in Phoenix to have it scanned. I was told that cylinder number two had a misfire occuring randomly. The car has just rolled over 38,000 miles. At 30,000 miles I replaced the fuel filter, spark plugs (NGK TR5's) and every other oil change I clean the MAF. When idleing the car will have a visible and feelable mis every once in a while and the stick will vibrate back and forth. I gapped the plugs to .056 as indicated in the manual range of (.052-.056). It was suggected to me to change the plugs again and run a 1/2 step colder plug NGKTR55's which I did this weekend along with cleaning the MAF again, and even removed the TB and upper plenum to clean the oil film residue. The car ran amazingly smooth for the first 80 miles but now seams to have the same mis every once in a while. The check engine light is not back on yet, but I figure it is a matter of time. Do these things normally have a twitch to them when they are idling? The cars power feels pretty smooth. Power mods only include a catted magnaflow x-pipe, K&N with silencer removed, and Steeda pullies. Last time at Firebird the car ran a [email protected] mph. I imagine if there was a terrible mis that the car would run slower than that. BTW, the car ran that on the older NGKTR5's. The new plugs were gapped to .050 in case you were wondering (AMP suggested reducing the plug gap to help ensure proper firing). Would it more likely be the coil or injector causing the prob? I checked the coil boots and they are all snug around the plugs. Thanks for any input and suggestions.
Kevin.

 

[sgarlic]

I'd remove that plug and re-check the gap, the torque on the plug, the COP, the connector, the injector, and everything relating to that one cylinder first.. and see if you come up with anything.

I'm not sure if what you're describing at idle is normal. My shifter moves back and forth a little bit, but nothing huge.. there is rumbling and a little popping at idle, but I don't know to what extent yours does it.

If you're going to be in Tucson any time soon, look me up and I'll take a look at it.

 

[The Stang GT]

Hey, I had the same problem. Your cylinder two, change the Coil on Plug, not the connector. You have to get a new Coil on Plug, and once you do that, you will not have the problem anymore. I had the same problem, changed the spark plugs, connecters, and still was getting the light, all you have to do is just change that coil on plug, and you are good!!!

 

[Mike97gt]

most likely you need a new coil. at least you have a code so you know what cyl is causing it.

 

[000104Mustang]

Thanks guys for all the responses. I was figuring I could test the coil by swaping it with another cylinder. If it threw a code on the new cylinder, then I would know it was the coil. If it continued to show cylinder number two, then I would know it was the injector. For my reference, how do the cylinders lay out on a Ford 4.6. I was told that number 1 is the passengr side bank front, with 2, 3 and 4 on the passenger side. 5 is the driver side front with 6, 7 and 8 on the drivers side too. Is this correct? BTW how much do the COPs run? Is this a part that normally goes bad or do you think it was a weak coil to begin with? Thanks again!
It hasn't thrown another code yet but it is steadily returning to the rough running motor it was before the 2nd plug change. If the weather holds out through this evening, I am taking it to Firebird again tonight. All I wan to see is 13.??????? I don't care if there are 200 9's after that 13, I just want 13. I finally bought a helmet just incase. Again, Thanks!
Kevin.

 

[CanadaStang]

Thanks guys for all the responses. I was figuring I could test the coil by swaping it with another cylinder. If it threw a code on the new cylinder, then I would know it was the coil. If it continued to show cylinder number two, then I would know it was the injector. For my reference, how do the cylinders lay out on a Ford 4.6. I was told that number 1 is the passengr side bank front, with 2, 3 and 4 on the passenger side. 5 is the driver side front with 6, 7 and 8 on the drivers side too. Is this correct?

8 7 6 5
front of car >>>
4 3 2 1

 

[Mike97gt]

do not assume if the code deos not move that it's a injector. could still be the plug even if it's new.

I have had a handfull of 4.6's with misfires that just had plugs done. many things could have happend to that plug. from a cracked insulator to fouling caused by the coil being bad. if that was the case you would get 2 misfires.