Misfire on cylinder number 7 DTC p0307
02-17-2019, 01:36 PM
#1
Thread Starter
Join Date: Feb 2019
Location: MX
Posts: 1
Misfire on cylinder number 7 DTC p0307
I have a mustang gt 2008 v8 4.6 3v
theres a problem with cylinder 7, p0307 when its not at operating temperature
i already sawpped coils, injectors(cleaned also), compression test good, new spark plugs, new intake manifold gasket, any fresh ideas?
theres a problem with cylinder 7, p0307 when its not at operating temperature
i already sawpped coils, injectors(cleaned also), compression test good, new spark plugs, new intake manifold gasket, any fresh ideas?
02-19-2019, 01:20 PM
#2
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
It's not an electrical misfire (coil/plug) That would be a P0357
A P0307 is mechanical and/or fuel related. Did you try swapping the injector with another cylinder or just the cleaning? Most modern injectors cannot be manually cleaned. They have to be put on a machine or adapted to turn on and stay on while cleaners are run through them (not just fuel with cleaner but actual cleaners).
Could be a leaking intake/exhaust valve. Compression test won't necessarily see a leaking valve since it only indicates instantaneous pressure and bad valve can leak very little. However, a leak down test would see a valve that is slowly leaking that a compression test may miss.
Could also be the emissions cmcv plate is sticking. They are these emissions type butterfly valves that are part of the lower intake. If you have buildup around one it will restrict flow. This thread shows the removal and replacement of the plate with ones that delete the butterflies. I'm only showing you so you see what they look like. in Removing them you would lose some lower RPM torque and HP and only have minimal gains on the high end. THey also require a tune if you remove them so, just for show.
Pic is on post two like 3rd/4th image.
https://themustangsource.com/forums/...l-pics-452819/
A P0307 is mechanical and/or fuel related. Did you try swapping the injector with another cylinder or just the cleaning? Most modern injectors cannot be manually cleaned. They have to be put on a machine or adapted to turn on and stay on while cleaners are run through them (not just fuel with cleaner but actual cleaners).
Could be a leaking intake/exhaust valve. Compression test won't necessarily see a leaking valve since it only indicates instantaneous pressure and bad valve can leak very little. However, a leak down test would see a valve that is slowly leaking that a compression test may miss.
Could also be the emissions cmcv plate is sticking. They are these emissions type butterfly valves that are part of the lower intake. If you have buildup around one it will restrict flow. This thread shows the removal and replacement of the plate with ones that delete the butterflies. I'm only showing you so you see what they look like. in Removing them you would lose some lower RPM torque and HP and only have minimal gains on the high end. THey also require a tune if you remove them so, just for show.
Pic is on post two like 3rd/4th image.
https://themustangsource.com/forums/...l-pics-452819/
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