My 91 240sx Wont go past 4500rpm when car is warmed up

[2easy]

So this is a new problem i am having. The car runs great when it is still cold but once it is warmed up it will not accelerate past 4500rpm just bogs down and backfires. I have not been able to figure out this problem yet so any help is great. Thanks

[PapaSmurf2k3]

Does it sort of hit that limiter hard, or does it slowly sneak up to it and then bog/backfire?
Have you checked your ignition and valve timing?

[blkvrtswp]

Check the cap & rotor for corrosion; check the spark plugs for too big of a gap; check the intake piping between MAF and throttle body for holes or loose clamps.

Also easy to check are main engine grounds and battery & main alternator power wire. Higher revs take more electrical power than low rpms.

None of that really sounds like it should change when warmed up vs cold, but they are easy to check.

[2easy]

i just put new plugs and rotor and wires i gaped them myself so they are right and i have been all over the maf and intake but cant find anything that would be causing the issue. When i put my foot in it it will go to 4500 like it should and then it just acts kind of like i am hitting a rev limiter and i dont have one so i dont know what else to look at.