I've gotten this code for the last 2 or so years but I clear it and its good for another 500 to 600 miles. I know what the code means but can't figure out the cause. The car runs perfectly fine and gets good milage too. All the vacuum hoses seem fine. I've already changed a few including the one to the FPR. I've also changes the MAF sensor and post cat O2 sensor. Makes no sense that it goes so long before coming on. It also never seems to come on while cruising but at low speeds like parking etc. any more ideas?? Thanks in advance.