Car wont go above 2500 rmps

[bahrec4]

i have a nissan 300zx Non Turbo 5 speed.i just had the alternator put in and now it cant go above it.i tried changeing plugs fuel filter checked the codes but nothing came up. friends think it might be the mass air flow sensor went bad but not surecar has 177K but engine was replaced less then 4K ago but only the block and suck no wiring done. please help need to fix fast thanks

[thaixcore]

make sure the MAF is connected.

[BigTDogg (MA)]

make sure the MAF is connected.

Definitely, then let the car warm up and check your electrical timing

[mn300zx]

I had the same problem, check your plugs, they should be nothing but NGK PFR6B-11. also check your timing, I have been seeing 15 degrees BTDC is the sweet spot.