Originally Posted by georgew48
Coming home yesterday I started getting an intermittent blinking check engine light. It would only blink a couple of times and only when going down hill with my foot off the gas. As soon as I pushed the gas pedal back down it would go off. The engine is running fine and no loss of power. My scan tool identified it as a code p300 which Is random misfire. Like I said no rough running and no fluxiuation in the rpm and no loss of power. MPG average was just over 7 mpg. Called the ford dealer this morning and they are going to look at it. Hopefully nothing serious.
Here's my first guess
Is your Check Engine Light haunting you from the dash like a tiny, orange, burning ember? If it is, there's a fairly good chance that a bad O2 sensor is causing the problem. These sensors go bad all the time. Some experts say that new fuels with higher ethanol content are causing parts of our cars, including the O2 sensors, to go bad prematurely. Whether this is the case or not, if your CEL (Check Engine Light) is on you won't be on the road much longer thanks to most states' inspection programs.
Of course before you go replacing an O2 sensor you'll want to be sure that's the problem. Even the parts are expensive, not to mention the labor if you're paying a shop to do the work for you. A Check Engine Light can mean a lot of things, and even though the oxygen sensor is often the culprit, there are hundreds of other possibilities.