Vacuum leak

[BlackCoffee]

I did the same repair last year after a rebuild. Just used a little silicon hose.

 

[BlackCoffee]

Check the lines and the EVAP valve next to the brake booster. I replaced that recently. Didn't buy the expensive Ford lines, just used silicone lines and clips. Two different size lines. It is actuated by vacuum (the small line) which could give a misfire. Also, the one line in the EVAP routing goes to the upper intake manifold behind the throttle body. You could have a leak in the vacuum system there. Here is a picture before repair. Replacing my valve solved my 446 code, but I also replaced the lines.

 

[Jdcline54]

That could definatly cause what you describe.
Although it might not be the problem. The only way to know is to fix the issue causing the p0446

 

[Msport]

I also had to replace the yellow line off of the evap valve next to the brake booster (blackcoffee's pic), I don't remember the code I got, but the line was burnt and causing the code.

 

[Nick Falcone]

Hey everyone just an update because I forgot to do it when I fixed this issue. It was the EVAP control valve where the spare tire is. It went bad. 60 dollar fix. My misfire was another issue 2 coils went bad cylinder 2 and 3 also the last person who did the coils snapped the screws into the plenum on cylinder 6 and 7 so the coils vibrated up. Had to tap them out. Thank you for all your help!

 

[Nick Falcone]

For the P0446 code you need to check the condition of the wiring harness/plug and the actually functionality of the evap vacuum control valve back there above the spare tire. Lower the spare to get to it. Sometimes that control valve just wears out. Other times it's the ground wire in the harness lead itself. Any little crack in the insulation of the wiring will allow corrosion to set in and disturb the current flow to the control valve.
Here's a good video describing the trouble shooting of the valve.

You were 100 percent right thanks for the help!!