I always find it helpful when members follow up on issues they’ve had so I thought I would do the same in case it helps anyone. What I have learned about my 4Runner is from this site and just tinkering. I hope this follow up helps someone else.

P0420 was my original problem. As I mentioned I tried new sensors, cleaning MAF & TB with no luck. I later had my cats replaced with some weld on aftermarket ones to keep cost down. This solved the P0420, so far at least. I don’t drive much.

Then later I had a P0440 code pop up (Evaporative Emission Control System Malfunction) which I haven’t had before. It was always the P0420. I had the smoke test done and it was the evap canister. I have the 2002 so the canister is above the spare tire and was in bad shape so I had it replaced. This has also, so far, cleared up the fuel smell I was experiencing.

If I have any more updates (good or bad) I’ll update the thread again.