To Dreama:
Well . . . hate spoil your dreams - "Dreama" but what you did was illegal. I hope you are not going to college in California because in some places here, they would confiscate the car, give you only a few days to put the cat BACK on, have it certified OEM complete by an EPA approved lab (including a stock or APPROVED PCM tune) and smogged to pass, and if you did not do it - depending on where it is they could order the vehicle off road use only and yank the registration- or order the car crushed in addition to a hefty fine. If you were caught street racing with it - it would likely get crushed in some areas.
Perhaps where you are they look the other way, but you just made your vehicle unable to be sold in many states. The guy who did this for you - if he has a real business could face a hefty fine for doing it, and likely did so because there is value in the stainless steel and platinum from scrapping the catalytic converter. So in essence he stole from you to sell your precious metals - unless he gave them back to you of course.
It is also a Federal offense to tamper with or defeat any part of the emission control system and any vehicle 1975 or newer.
The reason you cannot find an Oxygen Sensor simulator is because the leading set of fools who brazenly broke the law and sold these things - Casper's Electronics were halted, fined and basically destroyed by the EPA for making those devices. It was a $75,000 fine, they had to refund all money, and recall every single one of them. Read about it here =>
Casper's Electronics, Inc. | Civil Enforcement | Compliance and Enforcement | US EPA So . . . NOBODY will sell those things now - because even if they are caught trying to sell one on eBay - eBay and the seller will get fined. The injunction covers anyone who participates in promoting or selling such a device.
If you are just starting college, you must be a young man, but I am 53 and have been working on cars - and GM cars in particular - for probably as many years as you are old, and removing the back pressure required for an engine to develop the best horsepower can have a lot of effects - too many of which there are to list here - but let me say - I do fuel injection systems - and you say you removed (or want to remove) the Oxygen Sensor - also a Federal offense - and this is what controls the fuel injection system. If you do that you will put the car into "limp home mode" and it will get poorer mileage and higher emissions.
You may think it runs better and faster - and it probably is, will and does - because you are pumping more fuel through it than required and it will decrease the life of the engine and also cause a host of other problems I will not even try to begin to list here.
Some other poster here made note of the sound of a V-6 without a good muffler system or a glass pack setup. Every time I hear some yahoo who has put on a performance muffler to get a "throaty" sound from anything other than a good ole' V-8 engine - I laugh. Anyone with half a brain and an ear can tell the difference the louder you make it. A four banger will always sound like a four banger - pure crap, and a six cylinder - V type or not - with always sound like a drone machine a little better than crap, and the only thing that will sound heathy, hearty and strong is a V-8 with dual exhausts and an equalizing cross-over, - and I am partial to the GM small block sound.
Of course no one here is going to like what I just said - but here is food for thought. Since what this guy did was illegal; and you did not know any better; I would march right back over there and tell him to put it all right back on - for the same price he took it off for - FREE - AND smog the car to guarantee it is running right as from the OEM. He is liable. If he does not do it - report it to the EPA and the Justice Department will pay him a visit and make him do so and maybe yank his business license if he has one. That covers your tail in the meantime.
There are lots of ways to get more horsepower and better mileage lawfully and that is what we do - but what you did Dreama ain't it - so there is said.
All advice on the Internet is not good advice. Do not take it off - put it back on.


Bob