SC3_5SPD

94 SC300 2JZ 5spd 76k miles.

Poured a bottle of Techron fuel cleaner and also installed an aftermarket intake- I immediately got the dreaded check engine light.

symptums: shaking, and hesitation at around 4000 rpm (pulls back hard at some points).

Error code was 25 (system too lean)

Had to evactue FL during the hurricane like this.

When I got back home, roughly 6 gas tanks later I pulled the spark plugs and saw 4 & 5 were chalky and black. I replaced all the plugs and drove it for another 200 miles- symptoms remained

I pulled the plugs again today and found again 4 & 5 are chalky and black.

Before I install the OEM intake, replace the 2 plugs, all new wires, distributor cap and gas filter...

is there any other thing I should do or check before closing everything back up?

Any advise as to what this problem might be would be greatly appreciated, thank you!