So I was hoping that my second post here wouldn't be about problems but with any used rig they pop up I guess. Been working on getting the maintenance up on my recently purchased 08 1500 Vortec Max 4x4. When I bought it, everything seemed fine. It was a CPO from a dealer and it came with a warranty. I ended up changing the transfer case fluid, oil to Mobil 1 with a PF48 filter, flushing the coolant with new Dexcool, and will be draining and filling the trans with Valvoline Dexron VI Synthetic.

About 4 days after I bought the truck I heard a loud tick under the truck. Fearing it was the AFM lifters I started investigating with a home made stethoscope. Valve train sounded fine and couple of my pulleys need replaced but weren't making the sound. I recorded a video of the sound(click here).

Turned out the rear most exhaust manifold bolt was broken.


On the way to the dealer the CEL came on and turned out to be a P1174 code. Dealer took care of it without any issues, which surprised me. Even had me in a new Impala as a loaner. They had to pull the drivers side head to extract the bolt and according to their paperwork they replaced the head bolts, head gasket, exhaust manifold gasket, exhaust manifold bolts, and a few other things.

I picked the truck up yesterday drove it all of 80 miles. I swore I still heard a noise and took all the belts off and recorded it(YouTube link). Today while cruising around I heard a strange chattering noise under the hood as I was coasting downhill at about 55mph and the CEL turned on. Pulled the code myself and it showed P1174 again.

So I have another appointment with the dealership on Monday. From what I read before I even bought the truck this isn't typical so hopefully once these issues are sorted out it will be a good truck. It only has 64k on it and appeared to be well taken care of.

Anyone else have an experience with chasing down a P1174 code? I did some googling and found a few things but mostly on older rigs or modified trucks. This one is bone stock right down to the AC Delco air filter in the box.

 

P1174- Fuel Trim Cylinder Balance Bank 1


it's tough to diag that one over the net especially when you don't have a scan tool to do the tests/checks required

 

did you do a car fax or an auto check? west coast cars 5 years old dont have broken exhaust bolts.east coast or midwest might,do you know any history?

You buy this from Lithia?

 

I bought the truck from McCurley in Tri Cities. According to the Carfax they originally sold the truck in December 2008 to an individual in Warden, WA who had it serviced at the Chevy dealer in Moses Lake. Original owner traded it in in August 2013, must have just paid it off. The chassis and exhaust looks really good. Infact, the exhaust under the truck looks better than the manifolds do. I'm pretty sure it saw a lot of gravel road use based on the tires that are fairly new tread depth but show gravel wear.

The one thing I recently discovered was the hours meter on the engine... it has 3300 hours on it which seems pretty high for 64k. I kind of wish I had known that before I bought as that makes it pretty obvious the miles were not highway miles at all. Would have helped get the price down I bet.

I don't know if it's worth noting but best mileage so far has only been 14.8, purely highway with cruise at 65 mph. I attributed that to the 4.10 gears, but maybe it should get better?

The more I listen to the truck I'm kind of thinking what I'm hearing is a slight miss, but wouldn't it through it a misfire code if that were the case?

This is the first newer vehicle I've worked on. I'm going to need to get something to read codes.

 

Truck is back at the dealer. I had the chatter noise again. Same conditions, decelerating from 75 to 70. This time I had the DIC on the real time fuel economy and the chatter occurred when AFM kicked in. It did it twice more under the same conditions, but after that I couldn't replicate it. Sounds like I have a wood pecker under my hood.


EDIT:

Tech called, couldn't get the code to replicate and it only had one instance stored(from Saturday). They are replacing the O2 sensors and the tech is driving it home tonight with a scan tool.