backfiring then safe mode?

[240midohiofan]

ok, so my rb20 in my s13 has been backfiring and stuttering the past couple weeks. this came out of no where. Every time i let off the gas, then back on it backfires. its nothing huge but i notice it every time and it never did before. also, if i give it full throttle it will some times hesitate then go back to normal. this also is a new problem. now i have searched and i have seen everything from boost leaks to mafs. i have checked for leaks and i believe they are good. my mafs is a z32. i have a spare q45 so i was going to hook that up to see if it did anything. well before i did that i checked my safc2 to make sure my hot wire senor settings were correct and they were not. in was 1 and out was 1. (i have never previously messed with this, as i bought the car back in june as is). so i put it to 2 and 4 and it seemed to help. well i took it out for a test drive and everythign seemed fine til i got on the high way. in 2nd gear i gave it full throttle and it just hit a wall at around 4500rpm. so now i think my ecu is in safe mode. im going to pull the codes tomorrow but i am wondering if what i did could have caused any of this? sorry for the long post. i have searched this topic but cannot seem to find what im looking for. any help is apperciated and please dont flame. im still new to this stuff and learning everyday.thanksNick

[dtowngoalie]

Pull codes and check your tps.

[240midohiofan]

code is 12. maf sensor circuit. should i replace mine or clean it? ill also check my tps.

[USMCgetsome]

test voltages of maf then report back.