Hi a have a question, i just did a dpfi to mpfi swap. I wasnt sure bout the vacuum lines but i hooked em up pretty much the same as my freinds crx si. When i push the throttle about 1/4 way it revs up and down continuously. But the weird thing is is that if i push the throttle down more then it revs up jus fine the rest of the way. The reving problem ony happens at lower rpms. If anyone knows how i can fix my problem that would be great. Its a zc motor with wat looks to be a z6 intake manifold cuz the fuel rail looks like a bigger fuel rail.

 

need to burp your coolant system. you have an air pocket in the system or a dirty (i believe) fit valve.

search on air in coolant or burping systems. you will find a lot of info.

 

yea its possible you have air in your coolant system that you haven't quite worked out yet. also it may be that your iacv is dirty, or possibly the fitv is dirty. assuming the engine your using has one, but i don't think it does.. anyways heres the writeups for cleaning both.

https://honda-tech.com/zerothread/1575913

https://honda-tech.com/zerothread/1564019

 

the system is designed to kill the fuel injectors if it revs above a certain point at idle, the reason it doesn't do it when you're driving is because of the signal provided by the TPS, so in addition to making sure your vacuum lines are right, make sure you check your TPS and calibrate if needed.