Persistent "Check Engine" Problem w/ Silhouette
Purchased a 2004 Olds Silhouette last month with 110,000 miles on the clock. One-owner. Extremely well-maintained according to the Carfax. The guy had it in every 3,000 miles for service and had the tranny flushed at 50,000 and 100,000. On the Carfax, however, starting at around 90,000 and continuing until I bought it, were numerous "Check Powertrain Control Module" entries. I was a bit concerned at that, but I bought the vehicle anyway. Now I know what it meant.
Although the vehicle runs generally flawlessly, the "Check Engine" light is baffling numerous mechanics. The dealer I bought it from said the code read "O2 sensor," so they replaced it. Light came back on for me. Took it back to the dealer. "O2 sensor" again. Replaced ALL O2 sensors. Light came back. Took it back. Dealer got the "O2" code again but this time read further into the codes. Something about a PCV valve came up. Dealer found a tiny leak. Fixed it. Drove a bit. Light back on again. Dealer threw his hands up and said to find another mechanic, preferably a GM mechanic, and see if they can figure it out. Took to GM dealer. "O2" code again. Replaced oxygen sensors again. Light just came back on.
Now I know why the guy before me had it checked a zillion times, because it must have been doing this to him for the last 20,000 miles, too, and several dealers cannot figure it out. Anyone?????