Weird Acceleration Problem

I have a 2000 Protege 1.6L auto. My battery is going out recently and I went to Jiffy Lube and had them replaced it. Ever since that day, when I push the engine to 3500-4500RPM at full throttle, it will lose power for 1 second and then back to normal. If I turn on the overdrive and run at the car at 70MPH with RPM running at 4650, it doesn't seems to be going faster like there is a fuel cut or something like that. That started to happen when Jiffy Lube replaced the battery. The car has 84k miles on it and I changed the spark plugs, sepentine belt, cleaned K&N air filter at 80k and did a timing belt change and fuel injector flush at 60k. So what can be wrong??? I'm out of ideas here... (bang)

Check spark plug wires and ignition coils. They may have gone out by coincidence (I've found a lot of peoples' coils go out around 80-100k miles), or Jiffy Lube may have damaged them putting in the battery.

Not to be rough, but I wouldn't let Jiffy Lube within a mile of my car, especially for something as easy to change as a battery.

i have a 1.6 as well the same thing happened to me except even at idel the car would start to hesitate buck alittle when you give it some gas. turns out the alternated was going on the car. hope that helps

Alternator

If I keep lightly press the accelerator and don't let the RPM go beyond 3500, the car runs fine without any problem. As soon as the RPM hits 3500-4500 range, it will hesitate for 2 second and then back to normal again. It doesn't hesitate at idling.

Check your alternator voltage by measuring across the battery terminals with a multimeter while the car is running. It should be somewhere in the 13.8V-14.4V range. If not, also check your belts and everything to make sure one is not slipping.

I went to Auto zone today and had them check the voltage. I got 12.62v with engine off and 14.24v on so I don't think it's the alternator or the battery. I replaced the serpentine belt at 77k and now the car only have 84k miles on it. The belt tension has been adjusted to spec so I don't think it's the belt too. I pulled out my spark plugs and all of them still have 0.44 gap. The only thing I have not check is the coil packs, oxygen sensor and MAF sensor. I don't have a CEL on but now the symptom is getting worst. When I cold start the car at the morning and press the accelerator to 1/3, it will hesitate for 2 seconds at 2500-3000RPM as if not getting enough gas. This symptom goes away in 2 minutes and the car drives like normal. But when press more than 1/2 on the accelerator and rev the engine to 3500-4500RPM, it still have that slight hesitation for 1-2 seconds, but goes away after 4500 RPM. I'm running out of ideas here. (pissed)

^^Check your Air Intake Boot (the rubber one from the air filter to the engine manifold), there might be cracks along the flexible ridges. My car did the same thing when there were cracks, and as soon as I replaced it, the thing ran normal again.

I have the same problem...when i press full gas between 2000-3000 rpm there is like a electrical cut on the engine...its like if the engine is struggling to get some air-fuel...and its all disappear when im at 3000rpm and above. My uncle had the same problem on his 98 protege and told me it was a sensor problem (he forgot which one).