I bought my first honda last night. It is a 1990 civic with a d16y7 engine. Please bear with me I do not know too many abreavations. So to the problem. When it idles it will jump down to real low RPM's. about 300-400 then back up. Sometimes it will idle around 1400. When I'm driving its usually smooth, but if i let off the throttle or just barely give it gas it will sometimes jerk. On a few occasions it has stalled at idle. I took off the air idle control valve and sprayed it with carb cleaner. I did not take it apart all the way to do so, which I'm regretting now. This did not work and is the only thing I did. I'm about to buy a new one but they are expensive and A lot of different kinds and I don't know which one to get. Any help will be greatly appreaciated. THanks.