wildazme

Hi all, im having a problem with my 07 mustang gt. When i first start my car after it sitting overnight or for a long period of time i get a stumbling idle, it usually only does the stumbling idle when i first start the car after sitting awhile and once i start driving it goes away and does not come back. I checked for codes today because the flashing engine light came on for a few minutes and i got codes p0302, and p0316. anyone have any ideas why i might be getting these codes. I had my spark plugs changed about 6000 miles ago. i currently have 47700 miles on my car. thanks in advance for any help.

stealth_GT

Cylinder #2 misfire and misfire on start up. Did you do the plugs yourself? I'd check out the spark plug boots and pop them off, then put them back just to make sure that they're snug. How long have you had your Vortech belt? maybe it's getting loosen up and you may need a new one. I had the same codes on my 07 motor when I first installed it. Turned out the 07 spark plug boots, one was screwed up and I ended up using my 08 boots and it cleared it up. One of the accessorie drive pullies also needed to be swapped out for the 08 one.

06mach1

Flashing MIL is not good. Should not drive it too long as you will destroy the cats, that is if they are still there. Another possible issue could be an injector leaking down on #2 cylinder. After you shut it off, the injector leaks in to the cylinder flooding it with gas. Upon start up, the cylinder tries to fire and eventually does. As long as it stays running it won't misfire. Can be checked with a fuel pressure gauge. You might also smell gas in the oil too, which is not a good thing either.

wildazme

I had a shop do the install on the plugs, as for the injector wouldnt that cause it to happen if the car was parked for say 2 hours and i tried starting it , it would happen then. because it doesnt, it only does it when it sits over 8 hours. My supercharger belt is snug and in good condition. im thinking maybe a bad spark plug in cylinder 2.

06mach1

If it is going to leak down, it will do it right away, say within a 1/2 hour or so. Then what leaks out sits on the piston or the valve. Could very well be the plug also. Once the engine gets warmer, it easier to ignite. If you don't have a way to check fuel pressure (a gauge), then you might be better off pulling the plug as it has been out recently.

wildazme

well changed coil pack and have the same problem, so wasnt that

06mach1

Is there any valve noise upon start up?

157dB

http://iihs.net/fsm/?dir=10&viewfile...scriptions.pdf

808muscle

Did you pull the plug and inspect it? Maybe they used the wrong nickel anti-seize and it melted down fubar ing the plug.

SpartaPerformance

Possible causes:

• Damaged crank position sensor
• Ignition system
• Fuel injectors
• Running out of fuel
• Fuel quality
• Base engine
• Damaged PCM

Freeze frame data and the DTC p03xx are also stored, indicating which cylinder the misfire occured.

If you know somebody with a "REAL" scanner (not Auto Zone) they can read the data.