I'm having some problems with my car throwing various codes. First off, it always throws a code that my engine is running lean. Second, it says that I have a bad speed sensor and temp sensor. That's weird because I have a new speed sensor and thermostat in it. There are no vacuum leaks on the car as I know of. The oxygen sensors are brand new as well. (Are the oxygen sensors powered my fuses in the car? I noticed that I am missing quite a few fuses in the fusebox under the hood. Wasnt sure if that was normal.) I don't have the typical symptoms of a lean running engine like stalling, rough idle, and the such, but I do idle at around 400-500 rpms. The car drives fine except at highway speeds it j erks when letting off the gas pedal.