MindRage

Hey everyone, been dealing with this a while so hoping I can get some info here, I have an S197 - 07 mustang GT 4.6l 3 valve and for a while now I have been having loud popping noises coming from under the hood as well as getting the P0305 error code.

I moved the C.O.P. and spark plug AND fuel injector from (what i think was cyl 5) with one from the other side, reset the code and drove for a bit until the code came back and again... P0305 .. so i dont think it was that, but I'm also not sure i moved the right one so this weekend i will swap all coil packs, spark plugs and injectors from driver side to passenger just to be sure however, if it stays at P0305 I'll be back where I started.

Has anyone ever delt with a P030* or misfire code in conjunction with a popping or backfire from under the hood? if the musical plugs doesn't pan out im guessing ill need to take off the valve cover and try to peek at springs/ timing chain etc but to be honest im not totally sure what to be looking for

Thanks in advance

Dino Dino Bambino

If those tricks don't work, the problem is likely to be an intake valve that isn't closing fully during the compression stroke, causing reversion of gases back up the intake tract. Possible reasons are a broken valve spring or a bent valve. A compression test on all cylinders would then reveal reduced compression in the no.5 cylinder (front driver's side) so that's your next step. If confirmed, that's the time to pull the driver's side valve cover and look for a broken valve spring.

MindRage

Yea that's what mi afraid of... I've seen some videos on how to replace the spring but not so much the valve .. do you know if that is something I can do without pulling the engine?

MindRage

To add, I've been hearing clicking noises and think maybe the chain guide went and it may have slipped timing, would that cause only 1 cylinder to misfire like this or would timing slip cause more than just this issue?

Dino Dino Bambino

If the driver's side timing chain had skipped a tooth or two, the engine would run rough and all four cylinders on that bank would be affected.
Check the compression on all eight cylinders and post the results.

MindRage

Well... I swapped left and right side plugs/coils/ and 1 fuel injector, i could not do the compression test yet because the gauge i rented from AutoZone would not thread into my plugs, connected everything and its worse. I reset the computer and today checked the engine codes again.. P0300 P0303 P0305 P0306 so im now getting misfires all over. I double checked everything was connected and tight but will triple check again. with the intake off i looked at the valve stems and they didnt seem bent but couldnt tell

MindRage

Some values at idle if this means anything to you

JimC

That's part of the issue - you changed so many things that you can't follow what happened. Can you put everything back the way it was and start over? Once you have everything back where it was (assuming you know what you moved where) then confirm that the codes etc. are the same as when you started. Then you swap just one to see if the code follows that move. If the codes stay the same, then what you moved wasn't the issue, but if the code follows the coil that tells you it was the coil. If the code remains the same, then move the plug (after double checking your gap) and see if the code changed. Moving everything around you now don't know what the problem might be because you didn't eliminate one-by-one for the possibilities.

MindRage

Yes thats what i tried first before all this - was P0305 so i replaced cyl 5 with brand new spark plug and coil pack and it did not go away, that's when I came to moving things around. I'm still a novice I know





One thing to note when I did swap everything around, the Cyl 5 spark plug (on left) was pretty burnt even though its fairly new.

MindRage

Sorry Images are so big I couldn't figure out howe to resize them!