I was getting a CEL 20 & 41 because I was running a USDM p28 in my Canadian GSR. Yesterday, I swapped in a CDN p28 with my custom chip and no more CELs.

The car starts as it did before, pretty smooth.

After the car is fully warm, when I stop a light, I get a slight fluxuating idle.
My idle looks a little low as well, with the car fully warm, it sits around 600-650.

The only thing I changed was the ecu. The car also idled a little low 600-650 with the USDM ecu.

I've been reading a lot about this fast idle valve on the OBD1 TB? Could this be my problem? I have an obd2 TB on my JRSC b18c.

Is there a fix for this?

 

I reset the idle tonight, and it still surges when I stop.

Anyone have any ideas? The only thing I did was change ecu's from USDM to CDN p28.