So here's the thing, these cars are notorious for having the CEL on all the time for various reasons many of which don't require actually fixing anything because of faulty sensors. So, instead of paying a shop to do the diagnosis evertime my CEL comes on when would you recommend it getting looked at? I can go to Autozone and get the OBDII to get the codes, so what codes require taking this to the shop? I had our '97 in the shop because of a CEL and they replaced the valve cover gasket, the plug wires, the knock sensor, and I think that's it. A few days later the light was back. This was almost a year ago and I was so fed up I said screw it and didn't take it back. The most recent codes I've pulled are P0325, P1170, and P1173. Are there any recommendations on whether or not this needs to go to the shop to pay hundreds of dollars in labor to replace sensors that will fail again?

I appreciate any help, Thanks!

 

part of your problem is where you take the car to be repaired. p0325 is knock sensor. if you paid someone to replace the knock sensor a year ago, they either didnt do it, and charged you for it, or they did change it, but did not do it right. either way, you got hosed. you should start with a reputable shop, one that will stand behind their work. or, better yet, learn to do it yourself. the other codes are the oxygen sensors. if those codes were thrown right after you got the work done, they owe you a big refund. when the lite is on(not flashing) that means the ecu(control unit) has detected problem(s), and you need to get them taken care of. the car is still driveable, but it is not running at it's best. the ecu has overridden the bad inputs, and is probably using factory set default programs to run. which means you will not get the most optimum performance and the best fuel economy. kinda like running in safe mode.

dont make the mistake of thinking the quality of all shops are the same, therefore go for the cheapest price. also, the highest price dont mean the best, either. look for a shop that is clean and well organized, and has been there a long time. i would stay away from a shop that works on anything on wheels, and try to find a shop that specializes in your marque, and a few more. experience cannot be bought, it has to be earned.

 

Very well stated keninn. Could not agree any better about chosing a good shop and sticking with them. When you become a good customer, a good shop will take care of you much better then if you are a first timer and they will try to get all they can while you are there because you might not come back again. You definitely should not again be getting the P0325 code if the job was done correctly and the update knock sensor kit was installed on your engine. Have installed this update kit sensor on quite a few 2.5 millenia and have not had one come back in 6 years at current location. The 1170 and 1173 could point to a faulty O2 as keninn pointed out but could also mean other things as well. The detection condition for the codes is that sensor output did not change from a rich running engine condition (output signal not dropping below .45 volts for more than 45 seconds when engine was at operating temperature and rpm greater than 1150 rpm). This could also mean that the engine really is running very rich due to high fuel pressure, bad MAF signal, etc. At any rate you could be just cranking thru the fuel and these codes would be telling you that indication. Only way to make the distinction is to have it checked out by a GOOD shop and just get a good overall opinion on the matter.
I liked the point keninn made about "staying away from a shop that works on anything on wheels" Cars today are so complex compared to what was out not so long ago. Started working on Mazda exclusively in 1989 just before the Miata came out. Used to work on carbureted cars all the time that were so easy to work on because everything was all separate from each system. One computer ran everything and was limited at best. Max of 6 codes that could be stored for a fault that could be detected. Today the CX-7 has 16 different computers that talk to each other by a CAN network that communicates every bit of information by way of two wires that are twisted around together at the rate of precisely 6 twists per inch. Any more or less twists in the CAN wire and you can have an issue with communication. Code capability is now in the 200+ area. You can get the CEL to come on if the gas cap is not on tight enough or the engine does not warm up quite as quickly as was anticipated by the PCM!! Pick a good shop that knows your car and how it works. You will not regret the choice.