I have a 2004 Trailblazer LS. Only had it for less than a month with 43,000 miles. On my way to work this morning the "Service Engine Soon" light came on. It would not stay on constantly but would blink 20-30 times than quit for 10-20 seconds than blink for a short while again. Never would blink no more than 40 times. but than quit for a short duration. The vehicle seems to be still runnning fine. no rough idleing or anything different. What could it be? May stop by Auotzone on the way home to get them to check the codes. Just blinking intermittently, willl they be able to get a code?