3M makes a kit available at most of the better automotive stores for
cleaning throttle bodies and injection systems.  it costs about 35 bucks and
does the best job of anything i have ever used.  just hang the can upside
down, remove the breather, feed the tube in the throttle body, crank the
truck and turn it on.  the vehicle will smoke like a freight train for about
5 to 10 minutes.  this kit not only get the throttle body clean but also the
rest of the injection system.

if you run name brand premium gas this isn't necessary very often but if you
are running off brand fuels and especially the lower octanes it would not
hurt to service the fuel injection system yearly.  i run nothing but premium
fuel in all four of my gas burners from my own pump and still find it
neccesary to clean the injection system about every 50 to 70k.

in this particular case i would recommend having your truck scanned to see
if there are any codes.  even if it shows and 02 sensor cleaning the
injection system may clear it up.  you should also check your plug wires and
other easy to visually inspect components before you do too much in the way
of swapping parts.

have you checked to make sure the air cleaner is not restricted and other
really simple stuff such as vacum lines?
michael

I agree the throttle body is likely the culprit here. It would be better to
use throttle body cleaner vs. brake cleaner as the manufacturer typically
coats the inside of the throttle body with a non-stick coating that harsh
cleaners can remove, which can cause more frequent cleaning to become
necessary. Also, I remove the throttle body from the vehicle so I can clean
it better as most of the carbon buildup is behind the throttle plates. I
remove the idle air control motor and clean that passage as well as the
pintle on the end of the motor. You don't want to disturb the throttle
position sensor and you should try to keep the cleaner out of it. Hope this
helps.

Mike