Had our FIRST repair needed under the hood on our ordered/purchased in 2004 new 2004.5 Chevy LLY Duramax truck at almost exactly 200,000 towing miles. A new "fuel pressure regulator" needed - $142 plus labor for a total bill of $318.
Engine started flash surging last Fall when fully warmed up and idling to about 100 to 200 rpms over normal idle roughly every 4-5 seconds. Didn't affect driving or towing at all but was aggravating and of course would only get worse. Issue was a failed internal O ring in the OEM fuel pressure regulator which then no longer sealed. It's a bolt on regulator but have to remove hoses and a few other things to get to it which takes time or it would be a simple 10 minute job.
Truck has only been used for towing the 12,800 lb 5th wheel or carrying the big Lance truck camper since new 13 years ago, so a $318 repair isn't bad at all for 200,000 miles of excellent riding/driving very good mpg's and reliable heavy towing use! Yup, going to keep the truck a lot longer and why not? No regens or DEF used then and the bright red truck still looks like new with no dents or rust or worn upholstery either. We be's very HAPPY!!!