I am fighting a 95 Astro van, 4.3L OBD1 vortech. Came in for basic area smog inspection. Did well at 2500 with 3PPM HC and .02 CO. Failed idle with 131 PPM HC and .11% CO. With aprox 95,000 mi, had never been tuned and needed it. Plugs worn to .015 over and ro... Login to read more.