From GM TBI Forum:
to check the TPS sensor you just need a ohm meter (cheap analog VOM from
walmart or discount auto parts stores work fine)  Actually It needs to be an
analog meter.

The Sensor has 3 wires, one is a power in (5 volts with key on) the other
two are the outputs from the resister, one negative and one positive. (for
this test it doesn't matter which one goes to what lead).

Basically you hook up the leads of the ohm meter then operate the throttle
or the TPS lever in a steady motion from "idle" to "WOT"  The actual Ohm
value does not matter what you are looking for is the meter to sweep with a
steady motion while operating the sensing arm.  If you have a problem the
needle will jump around a little where the worn out spot is on the TPS.



Subject: Re: L05 idle problems

Probably The Idle air control. If you have a scan tool
you can check the position. 5-45 is normal. with the
key on and the engine off it will be at 100-150. This
permits more airflow at start up. If your engine that
you swapped in sat around for a while the IAC may be
stuck in the start up position. Had this same problem
when I swapped my LO3 into My Ventura. To close the
IAC completely--With the key on and engine off install
a jumper betwwen terminals A and B of the ALCL
connector (the terminal you use to check codes)wait
about 30 seconds you should hear the IAC closing. This
may loosen it up. I did this with mine and it works
fine now. -Rod-



From Fullsizechevy.com

• white coloring is a lean condition or new spark plug.
• brown is a normal fuel coloring.
• black soot is a rich condition.
• black and wet is a fouled plug.
• red/brown is usually a fuel additive or detergent.
• missing plug parts is detonation.
• brown or black streaks above the plug thread and white porcilin
• Means the seal is defeated and weak with gases are escaping (can sound like a header leak).
  

airdeano