[Michael2008pony]

I was out driving one day on the freeway at 67 mph in my 2008 V-6 4.0 Mustang Pony package auto transmission with 29,800 miles. I always run 91 octane 100% gasoline and I do drive it hard.
:myangel

I started going up a hill with the cruise control on A/C on max, when I felt a misfire. The check engine came on.

First place I went to was auto zone (same day). They pulled the code of P0442 (Evaporative Emissions Control System Leak) I checked the gas cap and cleaned it.

3 days later the light was still on. :so I had it checked out by the dealer and the P0442 was gone. I now had the P0303 (cylinder 3 misfire detected) and P0507 (idle air control system).

The Mustang used to idle at 550 rpm a little rough. Now it's been idling at 750 rpm smooth as anything.

Please help me out here the dealer:banana: wants a lot of money just to find the problem out.

 

[GrayPony]

Has the fuel filter ever been changed?
Check the plug wire where it attaches to the coil and plug for corrosion. You could also pull the plug and post a pic if it doesn't look normal.
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If the car seems to be running smooth and without problems, you could try disconnecting the battery for for 20min. All codes will be erased and adaptive learning reset. Drive the car as usual and see if the problem comes back.

 

[G.O. Stang]

You may clean the throttle body. And as said before, check the fuel filter, plugs and wires. Clean the MAF. Do some general maintinence and see if that doesn't help. If anything at least it'll perform better after the problem is found.

 

[Michael2008pony]

Thank you

I changed the fuel filter, but I have not driven the car yet I'll clear the codes as well. Hopefully they wont come back. A friend has my spark plug stuff, so I will get to changing them. :yelwacko:

Thank you for your help! :bigthumbsup

 

[Michael2008pony]

All fixed

I have changed the fuel filter, spark plugs and cleaned the throttle body. Then cleared the codes and all has been fine for 2 weeks.

THANK YOU ALL :bigthumbsup

Michael McElligott

P.S. the plugs looked really bad