So I have a 98 Integra RS with a jdm itr swap. I bought it with a chipped p28 ecu but i figured it would run better and get better mpg with the stock ecu so i picked one up. the engine was cold when i put it in so i didnt think to much of the high idle. I let it warm up a bit and just wanted to test it out and watch for CEL. Well never got a CEL but the idle stood high like around 1600-1700 rpms until i turned off the car and started it again the idle went down to around 1100rpms.

I know i should have adjusted the idle but another thing had caught my attention. When i pushed in the clutch, the rpms would not drop all the way down. went down to like 1600 rpms but when i completely stop it would drop down to about 1100 rpms. It was kinda weird to shift gears becuase i wasnt used to the rpms staying up there. I didnt even have to give it gas as i up shifted. The whole point of switching to the correct ecu was to get better gas milage. Right before i installed the p73 i filled up my gas tank and only drove around 65 miles with it and the gas gauge was already half ways. Im guessing i was wasting alot of gas becuase of the wierd idle. I was getting about 22 mpg with by chipped p28 which i thought was bad. After half the tank i just went back to my p28.

so my question is, Do i have a modified p73 or is this normal for a jdm ecu?

 

Your idle should not be that high.
It sounds like you may have a vacuum leak & or other issues.

If the car is not throwing any malfunction indication codes that is a good thing.
Next step is to check for vacuum leaks, make sure the distributor timing is correct etc.