Momentary rpm surge from idle

[Kent McLean]

Brian Sims wrote:
 > I have been unable to find a cause for an intermittent rpm surge
 > in my 1990 type 44 with an NF motor. I hope someone else has
 > experienced this and found remedy. It only occurs at idle, in or
 > out of gear and is only momentary. There are no codes and all the
 > usual diagnostics passed.

It sounds like an O2 sensor, but that should throw a code.
When was it last changed?

--
Kent McLean
'94 100 S Avant, "Moody"
'89 200 TQ, "Bad Puppy" up in smoke