I have a 2003 blazer. The truck has always run but the "check engine light" always stays on. I took it to my mechanic and he told me it was my crank case sensor. I replaced the part. As I was replacing the part, I noticed that there was a large build up of oil on the old part. I cleaned the section of the engine of where it came from. I took it back to get it scanned because the " check engine light " came back on again and it registered as the same complaint. He told me to reset it and to bring it back if I still had the same problem. He also mentioned that if I do all that and it still comes on that there is another problem even though the scanner picks up the problem as the sensor! Go figure! Stay tuned.

This problem started when the car was one week old. Bought it new and had it back 14 times for same problem. Each time repaired the light stayed off for a week or two. Now dealer wants $2,000.00 to replace all 4 O2 sensors which have been replaced three times previously only to fix it for a week or two at the most. Reason for low mileage is we are afraid to drive it for fear it will quit completely, that and the average gasoline mileage is 9.1 MPG. We are told it is running on back up system and might stop altogether and need to be towed. Worst car we have ever had and will never consider another GM product. Contacted Chevrolet Motor Division and now all records have been deleted from the computers, they show the car has never been in for any repair. Phony GM, this is how you preserve your reputation if you build junk. Will dump it as soon as possible and chalk it up as a very expensive lesson but will tell as many persons as we can about it. We have two other Non-GM cars both with over 100K miles and never had a service engine light on even once.