I installed a 395 cu in stroker and am having major problem with idle.

The engine will not idle with a 32B ECM Eprom, but will idle much better with the 6E ECM ARAP Eprom.

Can someone explain this to me? Whats going on?

I did throw a 31 error code with the ARAP Eprom, its not in my book.

ERR 31= Canister Purge Solenoid fault, EGR circuit fault , Map sensor circuit shorted,Low voltage, Fuel Injector fault or park neutral switch/governor malfunction.

This is what it says in my info.

Just my .02

I checked the fuel pressure with the engine running, so I disconnected the vacuum line the the AFPR, maybe that is why I set the 31 error code.

I'll disconnect the negative terminal to reset the ECM.

Then if the engine still idles better, I will do the IAC adjustment, set idle RPM, and check the static timing.