The idea that one injector was "down" 9% is interesting. Everybody is worried about burning exhaust valves when you lean an engine out too much but who knows how many MPFI engines out there are running really lean on one cylinder.

Perhaps the injector flow decreasing with age is responsible for some older cars getting progressively better mileage...

The WitchHunter Experiment is on.

The Caravan has 140,000 miles and at least five of the injectors are original. I didn't want the Caravan downed for a couple weeks while the injectors were in work, so I went to the junk yard and relieved a similar (except for the bashed fender) 3.8L Caravan of its injectors ($4.50/ea.) and sent them. When they get back, I'm going to do a major tune up. A tune up on a 3.8L Caravan involves taking half the engine apart, so I'm arranging it so that I can take it apart and put it together all at one time. Remanned injectors, plugs, wires, pcv valve, and hopefully, the upstream O2 sensor. Sure hope this helps.