# Diagnostic code p0306 2000 Mustang GT 4.6L **URL:** \ **Category:** NYSpeed Automotive\ **Created:** [July 6, 2013, 3:13pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614 "2013-07-06T15:13:35Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![POOPRA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/poopra/32/7188_2.png) [@POOPRA](https://forums.speedlife.net/u/POOPRA)\ **Post date:** [July 6, 2013, 3:13pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/1 "2013-07-06T15:13:35Z")
Ok I am trying to get my mustang to pass nys inspection, but it keeps throwing code P0306 cylinder 6 misfire. The car drives/idles fine, I cant detect any misfire when driving it normally or pushing it hard. After clearing out the code I swapped out the injectors, coil packs, and plugs to see if it would trigger a code for another cylinder. After about 20 min of driving the same code came back for cylinder 6. The car runs strong and I cant detect any loss of power. I am thinking maybe EGR ports are clogged? Just trying to decide what to try next?? ---
**Author:** ![2TurboZ](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/2turboz/32/7577_2.png) [@2TurboZ](https://forums.speedlife.net/u/2TurboZ)\ **Post date:** [July 6, 2013, 3:27pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/2 "2013-07-06T15:27:11Z")
EGR or PCV perhaps… No real good info on google beyond what you have already tried…the only strange thing I read was a bad valve ---
**Author:** ![honda4life](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/honda4life/32/5300_2.png) [@honda4life](https://forums.speedlife.net/u/honda4life)\ **Post date:** [July 6, 2013, 4:12pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/3 "2013-07-06T16:12:14Z")
Fords allow one code to be on when getting inspected. So you shouldn’t be failing. It doesn’t sound emissions based IMO ---
**Author:** ![nitroinsane](https://avatars.discourse-cdn.com/v4/letter/n/d26b3c/32.png) [@nitroinsane](https://forums.speedlife.net/u/nitroinsane)\ **Post date:** [July 6, 2013, 4:33pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/4 "2013-07-06T16:33:27Z")
It doesn’t matter once the check engine light is on it won’t pass. I would confirm you have noid at the injector,power/ground at the coil,and compression on that cylinder. ---
**Author:** ![LZ1](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@LZ1](https://forums.speedlife.net/u/LZ1)\ **Post date:** [July 6, 2013, 4:41pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/5 "2013-07-06T16:41:21Z")
Hows that plug look vs the others you took out? ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex034/uploads/speedlife/original/2X/b/b7170c8eddc0b95ece6b88172b2f416a08489a45.png) [@system](https://forums.speedlife.net/u/system)\ **Post date:** [July 6, 2013, 7:06pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/6 "2013-07-06T19:06:34Z")
Intake manifold leak? ---
**Author:** ![POOPRA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/poopra/32/7188_2.png) [@POOPRA](https://forums.speedlife.net/u/POOPRA)\ **Post date:** [July 7, 2013, 8:11am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/7 "2013-07-07T08:11:23Z")
Plugs all look fine, I pulled them all and #6 looked as good as the rest of them ---
**Author:** ![Spam16v](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/spam16v/32/5287_2.png) [@Spam16v](https://forums.speedlife.net/u/Spam16v)\ **Post date:** [July 7, 2013, 8:23am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/8 "2013-07-07T08:23:53Z")
cam lobe, follower, valve spring… compression, leak down, running compression comparison if electrically it’s functioning correctly. Interested to hear the result. ---
**Author:** ![Carnut](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/carnut/32/7590_2.png) [@Carnut](https://forums.speedlife.net/u/Carnut)\ **Post date:** [July 7, 2013, 8:46am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/9 "2013-07-07T08:46:39Z")
Make sure everything mechanically is in good condition. Check compression on all cylinders, if #6 is off by 15% from the others perform a leak down test. Once you have that data, it will be easier to diagnose whether it’s a mechanical or electrical problem. ---
**Author:** ![Darksyde](https://avatars.discourse-cdn.com/v4/letter/d/ed655f/32.png) [@Darksyde](https://forums.speedlife.net/u/Darksyde)\ **Post date:** [July 7, 2013, 9:45am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/10 "2013-07-07T09:45:06Z")
Same code popping in my BMW. pain to diagnose thus far. ---
**Author:** ![POOPRA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/poopra/32/7188_2.png) [@POOPRA](https://forums.speedlife.net/u/POOPRA)\ **Post date:** [July 11, 2013, 4:59pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/11 "2013-07-11T16:59:48Z")
Just got done with the compression test , all eight were in the 90-110 psi range. Feeling better with those results. Still haven’t found my problem though. ---
**Author:** ![POOPRA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/poopra/32/7188_2.png) [@POOPRA](https://forums.speedlife.net/u/POOPRA)\ **Post date:** [July 21, 2013, 9:21am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/12 "2013-07-21T09:21:14Z")
Can’t figure this out, inspected in more detail the injector & coil connectors/wire and they look good. Cleared the DTC codes and P0306 popped up again. ---
**Author:** ![Shifty](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/shifty/32/4959_2.png) [@Shifty](https://forums.speedlife.net/u/Shifty)\ **Post date:** [July 21, 2013, 4:06pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/13 "2013-07-21T16:06:29Z")
You might need new coil “boots” (these are cheap to buy and easy to get.) If your problem still persist…its most likely your COP driver for Cyl # 6 in the PCM. ---
**Author:** ![LZ1](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@LZ1](https://forums.speedlife.net/u/LZ1)\ **Post date:** [July 21, 2013, 4:25pm UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/14 "2013-07-21T16:25:33Z")
You try corral or one of the other mustang specific forums? ---
**Author:** ![POOPRA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/poopra/32/7188_2.png) [@POOPRA](https://forums.speedlife.net/u/POOPRA)\ **Post date:** [July 22, 2013, 4:41am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/15 "2013-07-22T04:41:02Z")
> [@Shifty](#): > > You might need new coil “boots” (these are cheap to buy and easy to get.) If your problem still persist…its most likely your COP driver for Cyl # 6 in the PCM. The coil packs are new, so the boots are new. > [@LZ](#): > > You try corral or one of the other mustang specific forums? Yep posted up on corral, not much help there ---
**Author:** ![Jeller](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@Jeller](https://forums.speedlife.net/u/Jeller)\ **Post date:** [July 22, 2013, 7:33am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/16 "2013-07-22T07:33:54Z")
If it can be PCV or EGR related could you have a leak in the system causing this? Smoke test for a leak? ---
**Author:** ![POOPRA](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/poopra/32/7188_2.png) [@POOPRA](https://forums.speedlife.net/u/POOPRA)\ **Post date:** [July 22, 2013, 8:07am UTC](https://forums.speedlife.net/t/diagnostic-code-p0306-2000-mustang-gt-4-6l/231614/17 "2013-07-22T08:07:08Z")
I was thinking EGR because I found some info on the about ports in each cylinder that clogged up, but then later verified that the 4.6 does not have these ports. If it was EGR/PCV related not sure why it would come up with #6 every time.