2000 5 speed maxima, my car feels as if it's losing power after 4k rpm it feels as if the power band is just flattening out.....could this be a knock sensor issue?? the car has no codes(or ghost codes). The car runs perfectly otherwise. Any input, fuel, spark, timing being retarded??

Thanks in advance

bad maf = mass air flow sensor

your MAF is fouled.

You know the funny thing is, I got engine oil in my MAF housing and my sensor still works.

MAF

If it's your MAF, simple... If it gets worse, especially hesitation early in the powerband, then probably alternator. Easier to feel in an AUTO because the transmission will knock and the shift points will be off. Battery and brake light stay off?

could be a clogged cat converter

watch your tempature should get hot and possible overheat if its clogged cat.

what if its a clogged cat converter..what should he do?...or if its the alternator?

does that also cause loss in throttle response

could be a clogged cat converter

playboi yes is does cause poor throttle respose.... mine would cut out at 35oo rpms mostly and would take forever to get to 4000....rough shifts and banging into gears was also something i had...

mine did that about a year ago, new MAF gave it all sorts of new life

Had the same problem, was the MAF.