loses power on 1992 Lexus LS400

My Lexus started losing power, check engine light comes on. Sometimes it resumes on its own, sometimes it will start back up via key, sometimes it does nothing. Computer says ignitors but the mechanic replaced both banks and it still happens. Help, help!

Asked by for the 1992 Lexus LS400
replace both ignition coils. also would change plugs wire or give complete tune up and fuel injection flush
How much would this cost? This sounds like what my car is doing.