When you clean the MAF, don't absolutely soak it. I use an old toothbrush for the not-electrical parts and a cloth and cleaner. I do give the electrical sensor a soak and let it sit on it's end to allow it to drain and dry. The MAF sensors can get clogged depending on which type you have. One make h...

I thought you might have done, but worth checking!

Neil.

Adding in my $0.02 worth here... High HC and CO are the result of incomplete combustion. It's trying to burn, but some fuel molecules don't burn at all (so you get HC), and some only burn part way (to CO, not all the way to CO2). This happens when you are running rich, too much fuel / not enough air...

Great explanations! I learn things here on MVS.

I do have a question on fuel pressure being too high. What would cause this? A bad FPR (fuel pressure relief) valve?

Another fuel related issue to watch for at this age is fuel injectors that are worn/dirty/leaking or failed injector seals.

Neil.

Maybe some new seals, injector filters (the ones that sit in the top of the injector) and some fuel system cleaner and every bit helps.

Maybe it just needs some fresh gas and a good old Italian tune up on the highway?

Neil.

Put 91 in there if you want to keep your engine long term and don't want to burn valves.

Neil.

Give it a good hard drive and 'tune it' with the right foot to try and clear all the line, muffler system, cat, and anything else that may benefit. Get the Techron and fresh gas running and it will be a better car. Good enough to pass, I don't know but you must be close. Glad to hear the O2 sensor s...

Sorry, just updated the thread with a possible source for the #34 option.

Neil.

Finding hard stuff is a fun exercise for me. Owning a 2000 V70R means trying to find many obsolete parts, especially on one year R specific parts like the back brakes, and AWD parts like bushes in the rear subframe.

I wish you luck on your quest!

Neil.