I recently had my engine rebuilt on a 1999 Prelude and after the tune (P28 Hondata S100) and everything my idle jumps up and down from around 400-1200. It also won't rev beyond 4k. My spec are:

ported head with blox cams
blox springs and retainers
aem cam gears
block sleeved with arias 87.5mm pistons
scatt stock size rods
kaizenspeed balance shaft eliminator kit
step decked @ .003"
skunk2 im
skunk2 66mm tb
aem intake
dc headers
apex'i n1 exhaust with stock cat

I was told that I need a bigger header and to remove the cat to improve airflow which is understandable, but would that be causing my problem?

 

When you say it won't rev beyond 4,000 RPMs, is this done with the transmission in neutral, or is the transmission in gear with a load on it?

 

It won't rev beyond 4k rpms in either case

 

I called the shop that did my tune and they said it could be my distributor or my iacv. My block was installed with a later model h22 oil pump so I had to install a later model distributor. Could have be causing my problem?

 

Well I went back to the shop and we tried a different s100 and that turns out to be the problem. The bad part is I got the s100 from another shop so now I have to wait until Tuesday to get a new one. Does anyone know how to fix a s100 that is in "limp mode" ?