Unless you have aftermarket, cylinder heads, cam or pressurized induction (supercharger. turbocharger, etc.) the Speed Density system will idle just fine. Fix any problems with the idle before compounding them with a Mass Air conversion. If you don't, them you will never know if the problem is with the Mass Air conversion or with the sensors and actuators reused from the Speed Density system.
The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the fixes & updates. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.
Yeah, what type of cam did you put in? My 87 handled quite a few mods without having to resort to MassAir. The only reason I really changed over, was because I was tired of the crazy idle whenever I would travel up a mountain, and the potential for future upgrades.