I have an 1995 LS400 inwhich the other day I did a stupid thing and flooded the motor with water while the car was off. I had meant to have kept the car running. After the motor was hosed off I tried starting the car, it fired up but idled irratically and the car drove like crap. As intended acceleration to 40 mph it felt like the wheels were going to fall off or the feeling that I was driving on two flats, hesitations and all. When I came to traffic lights and stops as I took my foot off the brakes it felt like it was going to cut off, the car shook like crazy I felt like a bobblehead doll. The next day I drove it to my brother's shop and used his air compresser tool to dry all the sensors, I took apart every plastic pieced hardware covering the motor inaddition to the spark plug housing and blew everything until I though things were dry..I had the same problem...Later that day I bought some Denso wires from the part store for $112 bucks, installed them and my problem was resolved, my car was back to normal. (the old wires had alot of water that settled in two of the wires on both sides of the motor towards the firewall) Now I'm on cloud 9..lol
If it happens to you, dry the sensors using an air compresser including the coil paks. And invest in some good spark plug wires. That should solve your problems because it did solve mine :D