gorm2

Engine started misfiring. Scan showed cylinders 1 and 2. 174,000 miles so I replaced all 8 coils and spark plugs. Ran like new for 2 months. Now missing again and scan shows the same 1 and 2 cylinders missing again. What now. I'd hate to go to Lexus bacause I know what comes next. They'll replace everything I did and I won't know.

V300Graham

The wiring to the coil plugs has probably aged badly. I've had to replace some wiring to plug coils on 2 of my older Lexi for issues of this nature.
Give the car to a competent auto-electrician and instruct him to replace the worn wiring to all 8 coil units.

RobRed

Agreed. Coils are suspect. Did you save any of the old coils? You could take 2 of them and swap into pos. 1 and 2 and if it fixes you have something killing coils.

diagtime

be careful with aftermarket coil packs. Yes, have the wiring checked/fixed if necessary.
injector problems are possible but quite rare. and since the problem went away with your first fix, coil pack wiring sounds like a good start.