car running rich and misfire

[yungnano]

I recently purchased a 95 LS400 with 240k miles and it started misfiring, with smoke coming out the exhaust and it would reek like gas. The codes I get are for misfires in cylinder 2, 3, 4, 6, and 8 as well as P0170. I replaced the fuel injectors with junkyard ones (cleaned them while tapping them with power) thinking it was that and didn't solve the issue. Then I put a new fuel regulator and it gave it a bit more power and way less fuel was burning into the exhaust. The regulator was toast I could hear the spring move around when you shake it. I put new plug wires, checked for spark to see if all the coils where good and they all got spark. I haven't done plugs yet but that was my next guess was either plugs, O2 sensors, or the fuel dampener or fuel filter. At some point oil change maybe as well since fuel might have thinned out my oil but does anyone else have an idea to what it could be? It is running very rich and smells like fuel into the cabin still but not as bad as it was before I swapped out the regulator. 

[paulo57509]

Before firing the parts cannon, I would check the ECU for capacitor leakage.

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/656360-all-my-crazy-lexus-issues-solved-ecu-leaking-capacitor.html