Purchased this 2013 GMC sierra in January of this year. Thought I had found me a great deal on what looked to be a great looking and well taken care of truck and a nice price. Very nice truck at low miles of 10,100. Fast forward 6 months and 5,000 miles later I head out for dinner one night and stop at a stop sign I hear a ticking. First thought was a passing vehicle. It just can't be mine it's so new. Stop at the next sign. Yep it's my truck. I quickly figure out it's only doing it when in V8 mode and goes away in V4. I dig around online and find out about the Active Fuel Management troubles. But mine has such low miles. The rest I read were up there over 50K mostly. The next day it was no longer ticking and didn't for about a month. Well a month later it does it twice in one week. Second time great I'm just down the road from the dealer. i will get there just before they close and they can hear it. Nope. In the 1-2 mile drive it shuts up. Take to them about it. Said there have been some problems with the AFM lifter. We set up a day and time to drop it off. The next Tuesday I drop it off and get a loner. Four days go by and they never get it to do it. They were willing to keep it longer but I decided to take it back. To me it was just too random at that time. Another month and about 600 miles go by. I notice it was idling rough. RPM would drop bellow 500. It had done this before and would tick in the near future. OK I need to get it in soon. I will next week. Saturday yep. Ticky tick tick is back. This time it keep ticking unless in V4. Again I wasn't too far from dealer but my luck it's just after closing. So I park it and call Monday. Tell them whats going on. Bring it on in. No loaner this time they are out. It was ticking this time. Said GM requires first thing they do is change oil and confirm tick. OK I get ride home drive my other vehicle. Get a call that after noon that it's confirmed a lifter. Have to take it back to dealer I got it from because there had been "other repairs" and the dealer that diagnosed it wasn't GMC Chevy only. Pick truck up next day take it to the other dealer. It ticks once on the way. Get there and while checking in I asked what other repairs were. The shocker. It was major engine repairs just before my purchase. Pistons. Rings. Connecting rod and bearings. I will be digging into this deeper to find out where such major repairs had to be done on a low mile well taken care of vehicle and how repairs on current problem goes. Oh and while I'm here. Got a 2015 GMC sierra loaner and your guessed it. Horrible headlights and ride like many have complained on here about. Even got the hard shifting trans.

Update from Oct 10, 2016: Got a call from service rep 10/7/16 late after noon. I call back the next day. I'm told "we can't duplicate the ticking" WTF!!! The other dealership confirmed there IS a ticking. Oh I was hot. Told him it WILL do it and has been confirmed by your other dealership. I have it on video! The problem is in the AFM lifters. video link: https://www.youtube.com/watch?v=Eb13yoSSC_c

Update from Oct 16, 2016: Finally after emailing the dealer the video of my truck ticking they have decided to replace all the lifters. For a low mileage vehicle. Less than 17,000 miles and this is the second time the engine will be opened up this is pathetic. The is will my last GM