CEL, VSC, Trac off lights on; poor gas mileage and fuel odor in truck.... on 2003 Toyota 4Runner

I changed all 4 o2 sensors, replaced MAF and used injector cleaner and still have all the same issues going on. Could it be fuel pressure problems? Faulty Power train control module? I don't see any gas leaks. Please help because I have no clue what it could be. Thanks!