I have been fighting this for a long time now I have a check engine light and the code is for the EVAP (evaporative emission system)
they told me it could be
1 defective or loose fuel cap
2 evap canister or hose cracked or not connected
3 purge or vent solenoid defective
4 vacuum leak at engine


now my truck is a 5.9 with headers cold air intake and a throttlebody spacer and a jet chip
now what i have done
1 new gas cap
2 found a cracked hose by canister and replaced it also replaced hose by purge solenoid
3 fixed a cracked hose by the battery coming from vacuum line under truck

now I found a hose under the truck with a screw in it caping it off near the headers and dont know if it was going to the stock headers or not

now i was thinking of replacing the canister or the solenoid they both are not cheap so has anybody else have this problem

 

i pull the ecu fuse all the time to reset the light and when the light comes on the truck idles ruff sometimes

 

i guess nobody ever had this problem

 

not many people in this section run with the 5.9 and have experience with it. Have you tried asking in the 2nd gen section?

Also, what is the actual code you get?

 

they told me the code was for the evap

 

Right but what was the specific code?

Also with the headers, are you running cats? Maybe a defective cat or O2. Need the actual code though

 

I think there are around 20 evap related trouble codes. If you could find out the exact one, it might help narrow the problem down.

P0440 through P0459 all relate to evap problems.

 

po442 thats the code

 

P0442 Evap Leak Monitor Medium Leak Detected

 

ok what does that mean where is my leak