[blazers27]

My check engine light went off on my 2005 with 100k miles. I had them run it for codes at Auto Zone and it came up as a "large vacuum leak". What do I need to check or do?

 

[Nismois4x4ONLY]

Need the code to tell you exactly, could possibly have to do with emissions.

 

[rcr_kx250f]

what engine do you have? and exact code would help. look under the hood for a diagram of the vacuum lines and start checking for a bad line or fitting.

 

[colin123]

fire it up, pop the hood, and start listening for the noise of air sucking

 

[TheOregonFront]

i would assume vac leak is under the hood, but gas cap most likely? theres not enought vacuum in the tank cuz of the cap and it throws a code? give it a shot

 

[nizmut]

vent valve on the vacuum canister. Bend over

 

[colin123]

how is the truck running, are the rpms dipping alot when sitting at idle?

 

[TheOregonFront]

did you ever find a code

 

[Mylt1]

im betting its an EVAP leak from the gas cap. but without the actual code it would be hard to confirm.

 

[TheOregonFront]

im betting its an EVAP leak from the gas cap. but without the actual code it would be hard to confirm.

see thats what i was thinking.

 

[blazers27]

see thats what i was thinking. Gas cap.

I think it has to do with the gas cap. The truck is actually running great. No idle problems whatsoever. It is running fine. Think I should try replacing the gas cap?

 

[nizmut]

get the code and run a search, the 05s don't have a filter on the vacuum canister purge valve. The valve gets dirt in it during a purge cycle. Bingo your hosed. It is a free fix until the warranty runs out on it. Then it is bank.
With 100k you are out of warranty, but see if your dealer will good faith you. It is a known problem, and there is a tsb on it