Recently, the power seems to have waned on my '98 V70 AWD (light-pressure turbo). Also, I took a trip yesterday on which I normally get about 24 mpg, but this time the car got about 21. Passing power/acceleration seems a little sluggish. The car has 201,500 miles on it. It was rainy and humid on yesterday's trip. I am wondering whether, with a car this old, I should just expect a decrease in power and mileage or if there is something I should do to restore her to her former glorious, energetic self.

Thanks

It's running rich. Possible causes: vacuum leak, worn out plugs, front O2 sensor wearing out, you're gaining weight...
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Keeping it running is better than buying new

I notice that I have not changed the plugs (or distributor) in about 3 1/2 years and 35,000 miles. Might be the culprit. Are there other items for a tune-up? Is the distributor a DIY job? (I imagine the plugs cannot be too difficult).

Thanks!

Plugs should last longer than 35k.

If it were my car, I'd first look for a vacuum leak as Klaus suggested. Start with the air intake hose. They wear out - look for cracks, splits, holes etc. If it has never been replaced it is probably overdue... If that is good, then I'd move onto checking all the other engine related vacuum hoses before changing plugs, cap etc.

Does the engine use any oil?

It uses a little oil, but not a lot. I think the 35K mile plugs are where I'll start. Seems a likely culprit. Then vacuum leaks. Thanks!

Another thought: When was the last time you changed the air filter? A badly clogged air filter might cause your symptoms. You could also check the air snorkel (intake) hose when checking the air filter. I once had a budding mouse colony in my 240's air filter box...:)

This is why I love Brickboard! I would not have thought about that! Thanks again!