Let me tell the situation. A while ago, my aftermarket air intake fell off. I would guess that it was off for about two weeks before I discovered it so I put it back on. Here is what is happening:
Slowly rev engine: it is normal can rev to the rev limiter.
Medium slow rev engine: Engine stutters but can rev to rev limiter.
Medium rev engine: Engine stutters more and can rev only to about 5-6k rpm.
Wide Open: Engine stutters a lot, can rev only to 4k rpm and bounces from 3.5-4k rpm.
Keep in mind this happens only with the air filter on. If I remove it, engine preforms normally. Also keep in mind that these issues happen if I am parked in neutral or driving.
My first guess was the air filter was clogged. So I took it off, cleaned it, and even removed the heat shield around it; this made no change.
My second guess, the ECU remapped itself while the air filter was off before I discovered it and the new mapping doesn't like the new airflow caused by the filter. So I disconnected the battery overnight to reset the ECU. This made no change, I'm out of ideas.
Any suggestions, ideas, hints, helpful comments are welcome and appreciated.