'89 Toyota pickup, 207K miles
Weather just turned cold - temp 15F - 40F now and this issue may be related or just a coincidence.
The issue: When I press on the brake, the idle revs up and slows down rhythmically. The frequency is two to three times in a five second period for as long as I keep my foot on the brake. As soon as I remove my foot from the brake, the idle returns to normal. The operation of headlights has not affect on this, nor does blinkers, heater, fan or any other electrical function (to my knowledge).
It is so noticable that it is almost embarassing at intersections. Sometimes kids next to me think I want to race them and I get funny looks. (For this reason, I take my foot off the brake whenever possible.)
Any help is appreciated. TIA
AG2