I have a 2007 Dakota with 4.7 V-8. Gives "gascap" warning on dash display and ck. engine light is on. Have changed gas cap. What else could be causing this? Is it something a very mechanically inclined person can tackle without having to endure long waits and high rates at a dealership?

 

Check the threads to see if where the cap twists specifically is stripped or damaged. Put your face parallel to the rear fender and try to see if the gas cap looks perfectly straight while it is snug and clicked on there..these things are a pain!

 

I have heard that buying anything other than the dealer supplied gascap can give headaches, but if it's not that then it's some other pressure loss in the tank I would think. These are some of the trickiest things to diagnose, between gascap and evap codes someone would eventually off themselves if they had to solve those for a living.

 

Only use dealer supplied (OEM) gas caps. For some reason these trucks hate aftermarket gas caps.

 

LIARS!

I have used and Advanced Auto one (broke the locking mechanism) and currently an Autozone one. I prefered the first one because it was an autolock style cap where as the new one is not. Check and make sure you didn't get a vented cap or that it is not in a vented mode, or two, make sure it is tight. I had the same issue when I bought my last cap. The reason was the cap had a vented mode and an unvented mode, which depended on whether the locking mechanism was depressed during locking or not. I made sure the cap was in the unvented mode and it has worked since and the code disappeared after the next start. Its definitely something with the new gas cap.

 

Mine was (07 dakota) small leak evap, gas cap, turned out to be pcv valve the hose rotted away. Put a new hose in cleaned the elbow fittings and that took care of it it's a pretty easy job if that's the issue just a little hard to reach since it's between engine and firewall. Just a heads up if you go that route the hose I got went above engine little but different of a fitting but works great