On my 89 turbo probe the EGR vacuum control solenoid made it run rough.(turbo only) first tried plugs, wires, newer gas, oil change, etc. finally found this to be the problem my scanner told me the EGR valve was bad but really it was this part that controls vacuum to the EGR valve also this problem was making it run rich and would idle up then drop real low and so on, to check this i think i unplugged the EGR position sensor, and pulled the vacuum line and it idled fine i cleaned the part real good and got lucky it ran good when i re-installed it go figure no part stores list this part, not even napa, so i really wish i had a pic to put up but yeah, and good luck finding good used turbo probe parts there hard to come by