1999 the idle go's up and down

[werewolf]

Hay guy's i've been looking and can't find it . Know i've read about it here somewhere. but my 1999 4x4 3.0 manual trans ranger , started yesterday when shifting gears the idle go's way up and setting at light the rpm go's up and down a little when the A/C kicks in and out. in texas warm enough for A/C. Thank in advance

 

[Jazzer]

Check your Idle Air Control. At idle, unplug it, the engine rpm’s should drop and it might stall- that’s good but not completely definitive.

-Jazzer