So my idle surges all the time. I have tried the cleaning fixes that are stickied on this site and others but it only works for about 50 miles then it starts surging again.

So I am just gonna throw down and get a new one. But they are not cheap.

My question is this:

Is there any big difference between the Hf Dx and Si's IACVs?

I mean could a 89 Si work in a 1991 HF? the reason I ask is because the part numbers are different on a couple of sites I have visited but the only one on ebay right now is a 1989 CRX Si IACV.

Would that work on my car?

 

you can swap in any mpfi iacv from a 88-91 d16a6 and 90-93 b18a1. there are slight differences but they will work.

 

I just called Honda and they told me that it is a different part number for the Si years. He doesn't necessarily know if they are different, but they at least have different part numbers.

But you are saying that there is no big difference?