I have a 1998 2wd Rodeo with the 3.2L V6 and I've been told that I need
to replace the Oxygen sensors since I've hit 200000 miles and my gas
mileage has dropped drastically.  I got the sensors and was going to try
to do the replacement myself but I needed to put the Rodeo in the shop
to fix a leak anyways so I thought I'd just have them do the install.
But they're trying to tell me that it isn't as simple as just replacing
the sensors... they say that it needs to be put on a computer and
recalibrated and then there's some other test that has to be done and
end the end they say the truck will have to stay there for several days.
Is all this true or am I being scammed?