I am also having a problem with a vacuum leak; however, I noticed a distinct change in the way my truck accelerates and sounds. It seems as if there is more strain on the engine and I hear it really sucking air. I took it to the mechanic for state inspection a few weeks ago and must have noticed it because the check engine light was off and the truck was running fine. Sometimes the sound goes away along with the check engine light; sometimes it will start back up again, so I'm just thinking it may be a loose connection somewhere.

I already checked the lines running near the tank as the above post described and they were in good condition. The sound is coming from somewhere under the hood though. Any ideas on where to start looking?

 

I started a new thread for you

Welcome to the site.

Are you getting any CELs at all? Please add your year/make and model to your profile. Mileage? What maintenance has been done?

 

For reference so you guys don't have to check my profile, I'm driving 2003 Ram 1500 4.7L.

Not sure what a CEL is

I bought the truck used back in October of 2010; as far as maintenance, not much has been done except routine oil changes and a new condenser fan. As far as I could tell when I bought it, the previous owner took great care of it, tracked all of their oil changes in their log up until 2008, didn't see any receipts for major work; most everything looked original.

 

CEL: Check Engine Light.
I am having similar problems, I can fee the truck work harder to achieve proper speed, more so than before. It also has a different sound of the engine rev. Hopefully someone can chime in with some insight.

 

What codes are you getting from the CEL? Have it scanned and post them here.

 

PO456

Gas cap/vacuum leak

 

PLEASE USE THE SEARCH FUNCTION.

At least once a week I post the solution to this code, which is to first replace gas cap and if that doesn't work to go to the FAQ section and use the map of the evap system to trace the hoses, looking for a cracked hose or broken hose clamp...

 

In my own defense, I had originally bumped a thread that was in the forums from a while beck because it seemed to be similar to my problem. rather than a mod directing me to the faq after I posted, they took my post and created a new thread. Thanks for resolving the issue though.