Have you checked/changed the oil ? Power steering fluid ? etc... Run the AC ? Kind of sounds like upper engine, Hard to tell from here. Accessory belt dry ? Did you let the engine idle until full running temp ?
A 17 year old in a 430 is Dangerous in itself...Something else happened, The car didn't just Fail all at once, What could be white residue from the overflow hose that would leave residue All Over ???
100% Concur with Billy...While your in there, Replace the hoses and serpentine belt also, And Clean all you can see...You will feel way better when it is all done ;)
The Coil Packs and Plugs have nothing to do with the VSC...Try resetting the ECU...Disconnect the neg. battery terminal for a few minutes, Clean the terminal very well and and reconnect. Let us know the results please.
Your Lexus already has a CAI, A Catback won't make any difference in performance, Just sound. A waste of $. The only way to go about an upgrade is add a Turbo and have a custom (FULL) exhaust made. That would be a proper start.
Thanks a Mint...Just a Joke anyway ;) That piece is a Bracket for the ECM...The Diagram I posted is a General Version Per Exploded View. There are always differences between model years etc....