Vacuum

[Jacobian]

Check engine light. Small vacuum leak in emission system. Comes on a week after clearing code. Any ideas

 

[Jim BB]

If you know where it is repair it ! if you don't you will need to take it in to a shop or dealer and have a smoke test done to find the leak in order to repair it!
and it can be as simple as a gas cap too!

 

[GTyankee]

first of all, what is the trouble code
any auto parts store will usually hook up their scan tool to your truck

if it is code p0456
first check your Purge Valve, it is near your Throttle Body

 

[Daw14]

Tighten your intake manifold bolts , they are loose. Thanks to Wild One.