sup h-t

got a bit of a problem here

i have a 91 std,b18a1,did the dpfi-mpfi,everythings swapped in and been running for about a month

im running a chipped mugen pr4(i know its wack)i havent had a chance to switch to a stock pr4

well lately my car has been backfiring like crazy especially wen cold, and idles really bad,almost to the point where it turns off.
i have a couple of things that might be the problem but not sure:
1. the chipped ecu
2.no o2 sensor

checked the ecu n its throwing a code 4 (ckp)n 16(injectors)

im not sure how to check/fix the code 4?





any help would be extremely appreciated
thanks

 

im leaning towards that chipped ecu...ive read countless thread after thread of people having problems with chipped ecu's.

ask a buddy or try out someone elses stock ecu before buying to confirm that the problem lies within the ecu