Im dont know if there is any correlation, but the code for my 2004 2.4L comes and goes. I should say that the check engine light comes and goes. It came on a while ago then maybe a week later it went off but the code was still there. A friend of mine cleared the code and after a few days the light came back on, same code. The light goes off again but code still stored. Its off at the moment. I have ordered an OEM gas cap to replace the factory one. I was not thinking that the gas cap was the issue, as it was always secured, but I have read that they can go bad, i.e. the gasket cracks or I guess some internal wear can cause a vacuum leak. It should be here soon and I will clear the code and put the new cap on and will see if the CE light comes back with p0456, which reads "very small leak" on the scan tool. I will let you know.