The dreaded "Check Engine" light is on on my Ford Ranger 95 STX SuperCab, 6V 4.0. The raster says it's "EGR" but nothing else. I've heard a lot about gasoline quality or the cathalizer, but the cathalizer is good and I can't change the gasoline. I'm in Brazil, where the gasoline has around 25% of ethanol on it. What can I fix or change to turn it off? Thanks.