Yes check valves are installed.

Thanks for replies. I'll eventually break it down to see what is up.

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Jim

Your timing chains are stretched at that mileage, they are only good on average to 170k miles, take the upper cam covers off and show a picture of chain tensioner piston , may be extended too much

Got the covers off. Everything is lining up fine. I did find one of the cam position sensors connectors loose and I may have had a leaking intake gasket. Not finding anything out of line in regards to timing. Bank 1 tensioner is sticking out further than bank 2.

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Jim

Here are tensioners. Bank 1 extends out more than bank 2.

The fault code was on bank 2 cam timing not at desired. Also I was getting an out of range high indication on the intake manifold pressure.

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Jim

Before I started disassembly it threw a check engine light, rough running and smells rich running. Misfire on 5 and 6 and the intake manifold pressure sensor was showing a number higher than spec at idle. I did find a cam position sensor connector may have been loose and one of the intake manifold gaskets had a tear in it (possible leak).

All of the timing marks are lining up. Once the cam hold tool arrives I'll pull cam covers to see if I can tell anything else about it.

The fault codes came up once the wife stopped (engine running at idle) after having been on the interstate running fine at around 80 mph for about an hour.

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Jim

I'm going to proceed with replacing the cam adjusters and all the chains and tensioners. hopefully it will make it another 200k miles.

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Jim

Yes the pictures show your chains are stretched enough to warrant replacement, did a car with same issue, i measure the tensioner stick out 10mm approx, thats enough, on a 278, my own 104 wagon engine with 225 k miles showed 12 degrees stretch, had low torque but high reving power , after changing it lots of torque returned