This morning after about 5 minutes of driving my truck started to stumble badly. During normal driving (coasting with the foot steady) while going up a incline, it will stumble like it's missing. At WOT, it seems to be fine. It also has a bad idle that comes and goes every few seconds, even in PARK. I scanned the computer and came up with a code: P0442 Evaporative Emmission Control System Leak Detected (Small Leak). I swapped gas caps but that didn't work. Any ideas? Last night, I did fill up the tank with gas, so could I have bad gas?

 

Mine showed this code and it was a small vacume leak over behind the battery (in front of the computer). My be it effected the egr valve. Try checking both.

 

I have the same problem with my truck. Exactly the same problem. Replaced gas cap, no solution. Added Techron, Helped but came back. Sometimes it run's ok for a while but then it goes to hell in a hand-basket and run's like it is mis-firing. (which it probably is) The EVAP Emission error relates to the Charcoal Canister, does anyone think it could be this? I am at a loss here. If Jupiterak is still out there, you had the same symptoms. Anything help fix it?

 

https://www.f150online.com/forums/sh...ighlight=p0442

http://www.v8sho.com/SHO/DTCCodeP0455.htm

 

I have the same problem with my truck. I read an article on it that states this is the hardest code to diagnose cause it can be a small leak anywhere in the system. The best way to find out where the leak is, is to take it to a shop that has a smoke machine. They pump smoke in and check the entire system to see where the smoke is coming out. I may have to do this, but I'm oing to check for any cracked hoses leading to the purge valve and charcoal canister. There was a small video on this in You Tube by Wells Vechicle Electronics.