It seems like my 2002 monte with 180,000miles isn't reliable anymore. Should I sell it and get something else? I'm wondering if it's all down hill from here. It seems like we fix one thing and something else craps out!

 

So now it's throwing the sensors code.
I would replace them both, (could be the CAT: failing/clogged) so that may also need replacing.
180,000 is a feat with any car, but if you feel like its done its job and you're ready to move on and can afford to do so, why not.
Most of us here will say, keep it, well because we hate to think about parting with our cars (we love em too much)
We the new info you've found on this site i would give it one more chance to see if anything can be done to salvage it.
Have you changed the Spark plugs?

 

Yeah, the spark plugs were changed right after the car crapped out. I really can't afford another car right now since I have a payment on a "07" solstice but I can't drive it in the snow here in Connecticut So you think we should replace O2 sensor and the CAT. How much is the CAT? The O2 sensor looks to be around 70 bucks. What's the worst that could happen if I don't change the O2 sensor and CAT right away? I really need to get through the next couple months without spending any more money on the monte.

 

If the cat has never been replaced, it is probably the cause of your problems. I can't believe the cat has lasted you this long without giving you grief. I bought mine used and about 3 months later the cat went with less than 80,000. A new cat, depending who you buy it from, can range between $120-$250. If you get one already installed on the downpipe, it'll be more expensive but easier to install, like this one:
http://www.zzperformance.com/grand_p...=551&catid=110

Most other will require welding the cat to the downpipe, which leads to extra costs, averaging about the same as the cat/downpipe setup.

 

CATs can last a long time. I have my factory CAT on my '94 Grand Am (with about 203,000 miles on it and it has great numbers each time I get my state's emissions check every two years).
Now, the '01-'02 W-Bodies (such as the Monte) had a mis-manufactured CAT and GM extended the warranty on them as a result (extended to 10 years or 120,000 miles, per special policy #05551). So if your CAT is the factory CAT, you are probably way over due and that could be the source of many performance problems. I really don't know how to properly check the CAT (so you may want to have an exhaust shop check it out unless someone here can give you the info to check it). I don't like throwing parts at a car without having a good level of confidence "Yep, that's what is wrong".

RockAuto.com shows replacement cats as low as $84. Some are weld in, others are the cat with down pipe (bolt in setup). Also check your local parts stores.

Also, keep in mind, you have a car with 180K on it. Not saying a car with 180K is not reliable (right now, I drive that '94 Grand Am and my Monte is parked for the winter as a result, and to think, I bought the Monte to REPLACE my Grand Am). But as your mileage goes up, so do some of the maintanance needs. For instance, I changed the head gaskets on that '94 Grand Am at 180K miles in October of '09. Since I did it myself, I feel the cost was well worth it.

 

Thanks for the replys! My Cat was replaced about a year after I bought the car new in 2002. It was one of the defective ones. What's the worst that could happen if I don't change the O2 sensor and CAT right away? Can it stall and not start like the MAF made it do?

 

Like Maniac said, higher mileage cars need more maintenance to keep them going. I always look at those costs and compare them to a monthly payment on a new car. So long as I'm spending less per year in maintenance than a new car would cost in payments per year, I figure I'm ahead of the game. Even new cars require some maintenance that isn't included in warranties and the like.

 

I guess that's true Kc2Kth

Cat was replaced along with 02 sensor. Car is running well but the check engine light came back on after a day. This check engine light is driving me nuts!

 

First, I assume your MAF is reconnected (if not, that's the source of a trouble code).

When that CAT and O2 were changed, did the shop reset the engine codes? If not, it takes a little time for the computer to reset itself (I had a failed O2 on an '05 Impala, took about a day of driving around before the computer cleared itself).

If it's running fine and does not clear in about a week, I'd have the computer re-scanned and see what codes it has now.

 

Were both O2 sensors changed, or just the rear one near the Cat? Because I believe you had the bank 1 sensor light on also.