Misfire? Sounds like Exhaust leak....
Changed all coils and plugs (Motorcraft platinum) on my '04 5.4L 3v but the same issue is still there since I bought it almost a year ago.
When I floor it (or almost floor it) from a dead stop or going very slow I can hear a puffing sound. I pretty much can't hear it unless the windows are down and it only happens in first gear - seems to be between 2k and 3k rpm. It always makes the sound once, twice or three times all at once. I do have a hole in my muffler but my manifolds are not leaking.
I was wondering if it was the hole in my muffler that's causing the issue due to a lack of backpressure but I can't help but think it's something ignition related. It actually went away at one point in time after changing the plugs but only for a couple of drives and then it's back.
All of my ignition coil connectors seem to be connected properly. I had it in to the dealership a couple times about it but they can't seem to figure it out.
would it help if I capture the audio? I'm not sure if I can post that here....
any advice is appreciated
Last edited by SCrew Lariat; 06-15-2011 at 01:16 PM.