Hello everyone,; I am new to this forum; hopefully I can get some help please. I have a 07 FJ with 165K. A while back I started getting a check engine light on and a scanner code of P0012 (left bank 1 retarded). My millage dropped down considerably. I poured some SeaFoam into the oil and that seemed to resolve the problem for a couple of weeks, but then the check engine light went on again. After researching on forums and YouTube, I decided to change the VVT solenoid myself as well as change the oil and air filter. I religiously change the oil (synthetic) every 5k. The engine light immediately went away and the engine seems to idle good and strong, but my gas millage is still sub-par at 12-13 MPG instead of 18. I had changed the solenoid with an off brand (doorman) instead of a Toyota OEM. The original solenoid seemed fine and was getting proper ohms . Any idea why I am getting 5 mpg less than normal/ and is their a relatively inexpensive diagnostic test for this issue, i am thinking its a timing issue, but i would assume the check engine light would have gone on. Thank you for your help in advance. P.S. I am not a mechanic by any means, just like to tool around on the weekends.