My check engine light came on about a week ago. How do you find out what the code is?

The only way is with a code reader, or a scanner. Take it to Autozone or Advance and they should be able to get the code for you.

Thanks!

Then.. w/o needing to say it. You'll come back here and look up the codes in Techinfo and we'll help you fix the problems.

Well, I finally got around to going to Autozone to get the code, and it issssss

DTC P0420 Catalyst System Low Efficiency

The guy said it could be a clogged catalytic converter, something with the O2 sensor... but he did say that it could be a number of things with this code. Anything that would be really typical for a Bonneville? I seem to read a lot about O2 sensors...

Oh, and if it helps, the only thing funny I've noticed about the way it runs is that it'* REALLY noisy, kind of like a truck :? and it seems to be coming from the back end, like around the exhaust or something. Other than that, it seems to run normally...

I'd have you lay down next to the car while it'* running to see if the noise is really by the back..or by the catalytic. Sometimes a hole will actually blow out the side of the catalytic when they go bad.

IIRC Haro posted this about his 95 back in the day.

Kick your cat. Up and down, side to side. Hear a rattle?

He means the one on the car Rach...lol

It'* possible the cat is clogged/bad.

I found out more things, I think.

My temp gauge always says like, 160 instead of being close to 200, which I know is wrong. I asked my uncle about it, and he said that would explain why the catalytic converter was clogged, because the thermostat is telling the computer the engine'* colder than it is, so all kinds of extra fuel is getting pumped... and... I think that'* about it. So, does this mean I need a new thermostat, and catalytic converter? He also said I'd probably need a new 02 sensor, why would that be?

Also, for the kicking part (ha), is the cat that big box thing under the car? :?

Oh, and I guess what I'm also asking is, could this all be related to a bad t-stat? It seems like that would be the root of everything. I'm getting terrible gas mileage too, I'm assuming that'* cause my car is using way more fuel than it needs to.