The throttle body needs to be cleaned periodically. You can do this
yourself for the cost of a can of carb cleaner and 20 minutes of your time.

Hi Greg.

I don't think there is any adjustment on the TPS (I think the computer
calibrates itself to it when you start up and drive), and other than
that it is either working or it isn't, and if it weren't working, you'd
know it from symptoms, and there is nothing you could do as a preventative.

There could be some value in cleaning the throttle body - that is the
only item on there that, IMO, has any real value - the other things, if
you're not having problems are probably OK - I mean, inspect the
throttle plate?  Check the throttle bores?  For what?

Possibly there is some residue buildup on the throttle body.  People do
have problems sometimes that are fixed by cleaning the throttle body,
such as the slight shake at idle.  That you can do by yourself fairly
easily.

So, bottom line, IMO, unless it is worth $79 to you to have them clean
the throttle body - something you can do yourself in 15 or 20 minutes
with a can of spray throttle body cleaner, I'd keep my money in my
wallet - spend $10 for a can of TB cleaner and DIY.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

Since I switched to Chevron gasoline in '89 I've had no need to clean
the fuel system.
I switched because a Shell additive was coating the throttle barrel
injector on my previous car- '86 Le Baron GTS. My Chrysler dealer
suggested I try the switch.