2008 Toyota Prius gas engine 60000 miles does it sound ok

I've noticed a loss of power and bad fuel economy with my 2006 engine with 160k. It sounds like a sewing machine and I believe the chain is probably loose. I'm just wondering if it's worth while to do the value/chain adjustment when another used engine will cost only $400-$500 when needed?

 

1. Do a cylinder leak down test
2. Based off your results, buy the used engine and have the head done over, have it checked for cracks, warpage. Then replace the valve guides, seals, and a nice multi angle valve and pay special attention to the short radius of the intake runners, the short radius always has an edge that affects flow. Then maybe some mild port matching to the intake and exhaust ports to the manifolds. Set the valve lash correctly after the head is torqued down with a TOYOTA head gasket. I'm about to pull mine and do it. Have your injectors cleaned, install higher energy ignition coils. Coils made a big difference on my 180k engine. I'm averaging about 58 with easy driving, and 50 driving it hard. Coils lessened my no load idle misfire, but it is still there. I noticed it got better when I richened the fuel mixture with the techstream, which leads me to a leaking intake gasket, worn valve guides, or dirty injectors, my long term Fuel trim is on the high end of normal, so that could point to a vacuum leak or bad valve lash. I also know there is an updated manifold, Toyota seemed to thing water pools inside the manifold because of it:s unconventional design, high reversion pulses due to the HUGE duration the intake cams have. Gen 2 intake cams on the 1nz-fxe have about 272° of duration, where the problem regular 1nz-fe (yaris,echo?) Has a 212° duration. BIG difference! So the Prius intake is kind of U shaped for long runners for torque and helps with reversion pulses.


XT1585 ?

 

We've had a few reports of Gen2 exhaust manifold holes possibly due to road salt in the Northeast. Not the tail pipe but right up under where the tail pipe attaches to the engine...that piece can rust out or split.

 

^^^yep. My gen 1 has a leaky exhaust manifold, exhaust leaks before the 02 sensor can cause a false lean condition, causing the ecu to overfuel the engine. XT1585 ? is that an average of multiple tanks? Gen2 cars have a bladder in the tank that affects filling depending on the temperature.

XT1585 ?