I have a 2007 SX4 Crossover with 138,000 miles. Haven't had any major problems with car since we bought it new. Recently the check engine light cam on. I scanned it and got codes p0300, 0301, 0302, 0303, 0304. Which should be a random multiple misfire, and then a misfire code for each cylinder. I've checked plugs and they all look good. Gas mileage has dropped of. New 02 sensors. Manual and couple of the mechanics at work say it could be a faulty EGR valve. The manual I have says "if equipped" for the EGR valve and I can't find one on my car. So, I'm assuming I don't have one. Any help would be appreciated. Would really like to make this car last a few more years.