NOISY ENGINE!!!

[ncrow02]

So last thursday my 2004 PT (base model.. no perks... no whistles) starts making some weird noises... it sounds like the engine is gonna just take completely off! like a suzuki dirt bike or something.. loud revving. i get to about 40-45 and the noise is just so loud i can hear it over everything. I've been noticing my gas mileage has been just terrible lately too. So the check engine light comes on, and I call the dealer and make an appointment. I bring it in on Tuesday and the guy calls me and says that it's my rt rear wheel bearings, and my front lower control arms. Gonna be about $1250! The car has 52,000 miles on it. I've already replaced spark plugs, wires for an idleing problem at about 20,000. So i dunno.. so i tell the guy OK... arms are covered by extended warranty. $100 deductible, $250 for the wheel bearings, $50 diagnosic fee... much better than 1250.. well he calls back and says that didn't get rid of the noise. So now he wants to do the other rear wheel bearings.. so i ask him.. how do wheel bearings set off a check engine light.. and he says "a check engine light.... ????... your light is on?" "well, it was when i brought it in.. and i told your service guys that on the phone when i made the appointment".. so i tell him to hold off on the other bearings and run the codes.. (which by the way i already got charged for.. and find out he didn't do till i told him the light was on) and he comes up with the "down stream oxygen sensor" fault code. Gonna be another $300 for that. I didn't trust this guy all of the sudden and told him i would pay for work done, and would be by to pick it up.
So my question is... the noise is in the engine... it's constantly revving LOUDLY. Is this the oxygen sensor? at 52,000 miles?? and would fixing this get this to stop??
ANY comments would help.. i feel like i need to get this fixed asap and dont' feel safe in the car.

[CREWZIN]

Welcome to the forum. Advise......get your PT and run/drive as far away from that crook....errr, I mean dealer as fast as you can. You've been ripped off and he's trying to do it again with the 02 sensor. Luckaly you had the extended warranty and didn't pay too much.

Take it to almost any decent auto shop (Goodyear, Firestone etc.) and tell them to replace the 02 sensor that by the CAT, or do it yourself for a fraction of what that dealer wanted for it.

Noise is hard to diagnose over the internet but the 02 sensor shouldn't be the reason for it. It could be a faulty or malfunctioning IAC (Idle Air Controller) which would make the engine rev oddly but that's only a guess. Ask around and find a trust worthy mechanic.

[Cartman]

could be a bad catalytic converter. broken catalyst inside could be plugging the exhaust causing god awful racket and terrible gasmileage, as well as setting off your o2 sensor code. the downstream sensor is there to monitor the health of the cat, so maybe its telling you something....