HELP! Have I killed some sensor? NO POWER AFTER Headers and Cold Air Intake

[pasapaca]

This is my first time posting here. Sorry if this issue has been covered before.
After installing headers and C.A Intake. Revs went to near ZERO! actually the engine stopped 2 times. I guess ECU just experimented some strange modification. After 2 days revs went a little bit higher, just enough to keep engine running on idle. BUT ACCELERACION AND RESPONSE ITS MUCH WORST with the modifications. Above all, this orange light indicating some kind of trouble in the gas emission system was turned on for like 4 days. Te guy told me it was because he had to unplug some kind of O2 or emissions sensor when installing headers. In first gear, at not to heavy climbs I need to rev the engine to 4 o 5K just to be able to initiate movement (is it something wrong with the clutch now?) 0 to 60 in about 26 secs!
Anyway, I´m lost here. Just bought and installed new set of pulleys (Microimage) and...well nothing better. Is this usual?
Is it the clutch?, some damaged sensor? Feels like the engine is running with 3 cylinders! Perhaps a damaged spark plug? but why?. Any Help would be greatly appreciated.
Thanks a lot guys!