Check Engine Light / Multiple Codes / Runs Perfect / 07 SRX Cadillac

2007 6 Cylinder Cadillac 87,000 miles
So the other day my check engine light came on constant. Took it to an auto parts store and got the following codes:
P0523 Engine oil pressure sensor circuit high voltage
P02179 System too lean off idle bank 2
P0300 Multiple Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0306 Cylinder 6 Misfire Detected
I have re tightened the gas cap.
Checked all fluids (all good).
Disconnected the battery, check engine light went off.
Drove it for a day all good, next day check engine light back on.
THIS CAR RUNS PERFECT.
I need help! I am so worried that is repair will be very expensive and I don’t want to buy a new car right now.
Please advise me on what you all think might be the problem and how much it might cost.
I am worried that even the dealer might start just replacing parts in an attempt to figure this problem out.
Sincerely, Sleepless, Sad and Blonde in South Dakota

There are many complaints concerning the timing chain.Most owners had the timing chain replaced.

I would not think that a cam chain would cause the codes you are seeing. Maybe a worn through wire for the P0253 and a bad fuel injector the rest.

You don’t really have any choices here. You could continue to drive this car and more expensive damage can occur from the misfires. Take it in to a good local, independent auto shop for a diagnosis and estimate. Ask your friends, Yelp, CarTalks Mechanic’s Files, Google, whatever to find one.

The shop should want to charge you a diagnostic fee. You will WANT to pay for the diagnosis time because a good mechanic NOT throw parts at it, they will find the actual problem. They need to be paid for that time. An estimate to repair the car will come from that and you can decide what to do depending on how serious it is.

You might as well have the problem professionally diagnosed and obtain an estimate for the repairs. At that point you can decide, based on the repair costs versus the value of the car and urgency for having the work done, whether to fix it or keep driving as-is.

If the problem is something very expensive, and you live somewhere that does not require emissions testing, then you can just ignore it and keep driving until it no longer runs well. If you need to pass an emissions test soon, then you will have to figure out a way to keep the code from coming back, at least long enough to pass the inspection.

I live in Arizona, and only two counties here require emissions testing. People who own cars which run fine, but have expensive problems keeping the CEL on generally do one of two things: sell them cheap to people who live outside the emissions testing zone, or get a P.O. box or friend/family member’s address outside the emissions testing zone for registration purposes.

This morning I pulled the gas cap. O ring is missing. Going to get a new one with O ring. Wish me luck.

Got a new gas cap $10.00, just a Slant brand (not the best I know). Called the dealer that had one in stock ask him to pull it and look for an o-ring, was told it doesn’t have one. Wish I had done this step before. Disconnected the battery to reset the check engine light.
So at this point I pretty much know that putting a new cap on with not fix my problem.
Called a good mechanic in the area and have an appointment Wednesday morning.
At this point I will drive the car today and tomorrow or until the check engine light comes back on so the mechanic can read the codes. I also have pictures of all the codes that were displayed just the other day.
I will see the cost of the repairs them compare them to the private sale value of the car and go from there. Thanks for all the time everyone has given me in replying to my request for help.