99 Protege has problem bucking/hesitation under WOT

[maxt]

The car is a '99 Protege with 1.6l engine and 5-spd manual trans.

I bought the car a few months ago and have been slowly repairing the small issues with it. The thermostat was stuck open so the engine was never really heating up, and when i replaced the thermostat is when my hesitation problems started.

Under wide open throttle, the engine pulls fine until it hits ~4100 RPM. Then it starts misfiring and bucking like a bronco. If you keep it floored, it comes out of it around 5500 rpm until redline. If you have 1/2 throttle, the car accelerates fine regardless of RPM.

Before I replaced the thermostat, I used to notice a tiny blip at the same RPM (4100) but thats all it was. Now that the engine reaches proper temperature, its become an annoyance.

I have checked the plugs and they looked raggy so those have been replaced and gapped properly. My inner instincts are telling me the MAF or ignition coils are probably at fault, considering the mileage (170k), but I'd like some other opinions. The CEL is not illuminated.

[maxt]

I've resolved the problem 100%.

After posting I went outside and not having a MAF to test the old one with, I disconnected it and went for a spin. The stock values in the ECU were better then driving with the maf connected! So I took it out and low and behold, it was covered in a thick grime. Im assuming oil from the PCV coated the element over the years and dust stuck to it. A quick clean and the car feels better then it has since I got it.

So problem is resolved, and hopefully this post will help someone with this problem in the future.