Engine Flush?
 

I have a 2008 Accord, it recently started to miss fire, the code said piston 3 missing. The Honda dealer said I needed a complete ring change, I said bull****, there is no blow by, and I changed only the #3 plug to see, and it runs great now. He wanted to charge me $5k. What a scam. But I am going to change out all the plugs and coils. One mechanic suggested I flush the engine and adjust valves, he wants $1300. i have great compression and power and I’m leery of “flushing” the engine. Is it worth it? Do the valves really need “adjusting”,
thanks for any advice

Don't flush it. Save your money and possibly the engine. If the engine has had regular oil changes there's not need and it not regular the flush has a good chance of loosening sludge that gets into an oil gallery and BAM you need a new engine. No valve train noise. No need to adjust valves. Drive it.

Would not flush the engine especially if you have been changing the oil on proper intervals
Flushing would loosen particles you would rather stay where they are.
Otherwise they could end up somewhere they do not belong.

Honda engines are known to need valve adjustments after 100k miles.
My used CRV has recently hit 110k miles
But, no issues. So, I am delaying the valve adjustment which I might do myself.

Thanks for your advice, I just changed plugs, coils and used some injector cleaner, it runs like new

Thanks!