2008 Drain bad fuel from the tank

Gas removed, procedure went well. Added 5 gal BP regular. A private professional Prius mechanic recommended that the ECU would need to be reset by disconnecting the 12v battery to dump memory, just in case it had acclimated to some bad combustion characteristics. That was done tonight as well. Fired up the motor. No change.

My next thought was to change the oil to Mobil 1. My 2004 with 350k runs quiet and smooth.

 

Solid lifters - not easily adjustable.
I just looked into this on the forum, one thread had a 25 sec video of the sound, it is exactly like my engine. Everything I read says not to mess with adjustment, better to just drive it or do an engine swap for a lower mileage motor.

I have not tried an oil change yet, any suggestions on viscosity or additives?

 

Yeah Ed, I'm busted.
The oil looked fine, not dark at all, it was pretty well maintained, so I was told, but it had been sitting a while, over a Michigan winter, it had hornet nests in several places and the last date of service was 3/16. So figured bad gas.

 

Oil and filter changed, Mobil 1 5w/30 = no improvement, Added 1 qt 0w/40. Maybe it is a little quieter. One of my resources recommends Nano Pro NT or Lucas I hesitate to add oil modifiers.

 

I was able to figure out the answer regarding solid lifters, they are difficult to adjust, they use shims which is a lengthy process.

 

My engine with all of the concerns was replaced due to significant rod bearing tick noise and I now have Power on.
The salvage yard motor (112K miles, 2008) runs and works well. The test drive was successful, everything returned to normal. The hybrid system recharges while driving very well now.

Thank you for the help in the postings above

 

Earlier in this saga I did check the clearance, amazingly they were still close to spec, but the problem was on the opposite end of the motor.