i have a '94 Runner with a v6 and it has been running rough latley. The idle sometimes goes as low as 450 while at a stop. I brought it to the dealer and they couldn't find anything, not that i think they tried that hard. Does anyone have any sugestions. Tuned it up about 6 months ago and the idle problem poped up about 2 months ago. I had replaced cap, rotor, wires, recharged the air filter(K&N), run some techron through and even use 93 octane gas and still get her to smooth out or to get the idle consistant. It has 143,000 on it and I never have had any problems yuntil this one. Could it be the O2 sensor? it has never been changed.

 

Just an idea - maybe try cleaning your throttle body. Seems to help the guys with 3rd Gen's that idle rough occasionally.