Glen,
Realizing that 5KTQW's aren't my usual specialty, but kinda sounds
like an expiring oxy sensor. If the car runs fine otherwise, log your mileage
and see if it meets your expectations. I've an '84 4KQ that hunts in the same
pattern, worse when cold, that tested out bad when we checked the sensor.
How'd the TQC prollum work out, BTW?
-Chris Semple