Isuzu Forums - Isuzu Enthusiasts Forum - 2.3L Vacuum and MAP Sensor

I recently purchased a 1988 Isuzu pup with the 2.3l and know very little about these engines. The truck has a check engine light, O2 light, and fuel light on. The fuel light flickers or blinks randomly which is odd. The truck give me a code 23 which I believe is a MAP sensor issue. My main concern is getting the check engine light and O2 light off. The previous owner put on a new carb and a O2 sensor and the truck starts and runs fine. There are some vacuum lines that are plugged which I am not sure if it is because of the carb that is on it or a delete of some sort. Where should I start to resolve these issues? What deletes could be done on these engines?