'89 iroc 305 700r I have replaced the iac, tps, and maf sensor...i cleaned the butterfly assembly and the iac port...tps is set at the correct voltage...This problem comes and goes but here lately is more often...car idles (in park) at 2500 rpm...in drive stopped at about 1200 rpm...sometimes however the car runs perfect, idle in drive at about 600 rpm...some times i get a maf code (check engine light)...could i have bought a bad maf sensor?...it came from advance auto...also, if i unplug the maf the car idles correctly (but it smokes)...any suggestions??..this problem started about 2 weeks after i replaced the above parts

 

Yes you could have gotten a bad MAF. Also, there are certain kinds that wont work well in our cars. Cant remember which brand though. Do a search and you should find it.