our 1994 ford ranger 4.0 is almost complete with the first rinse arx phase. currently about 207,000 miles on the odometer. the hydrocarbon emissions dropped from 46 ppm (last october) to 4 ppm (last week). actually the lowest hc reading ever for the vehicle that has been tested since 1995 (previous low was 6 ppm in 1995 & 1996). can't say for sure it was the arx, buy it sured didn't hurt.