ok heres the deal we gotta 2004 trail blazer ls with the 4.2 liter and it has 32,350 on it. we bought it used in Jan 2006 when it only had 21,200 on it. my wife has always wanted one.
we had the truck 10 months and the check engine light came on...no biggie just an O2 sensor(upstream).dealership replaced. light out.
now, fast forward to june 27 2008.....check engine light on...O2 sensor (downstream). i replaced and light goes out.
july 3 2008 check engine