RB20 boost/maf problem

[Salar]

good day! looking for help!!

so the story is, my maf has been faulty for a while now, and the sign is that car turns off randomly at redlights sometimes, or acts funny as in wants to stall in getgo or in 3rd gear while accelerating. but this was not happening all the time, in fact it acted normal even under 14 psi boost and car pulled pretty good.

now, i just replaced the maf with another second hand one, supposedly an RB20 which looks identical to my previous one. after installation last night, i went for a drive, and noticed it didn't try to stall or turn off randomly at stops, however there is another problem now. car seems to be running too rich under half/full throttle and as it starts to boost up around 7 psi around 4500 rpm, the AFR reads 10.0 and car starts to act funny like something hits a limit, it doesnt want to rev/boost up anymore and normally this is followed by some backfire which i am assuming is unused gas hitting the exhaust.

any thoughts? does this mean the MAF is faulty?

appreciate any help in advance!

S

setup

rb20
gtr injectors and fuel pump
gt2871 turbo
apexi air intake
3" turbo back exhaust
nistune chip
greddy profec boost controller

[Skym]

Around 5000rpm there's a safety revlimiter (fuel cut). Check ECU for fault codes. Could be faulty knock sensors, knock sensor loom or anything banging against engine setting knock sensors off. Even ECU tune could be off due to being tuned with a faulty MAF and making engine knock.

If have Nistune, connect laptop up to car. Then check for fault codes and check knock count level, look for knock on dyno (with headphones and via ECU).

[Salar]

will do that. need a laptop first though.

thx a lot.