Engine Performance problem
2002 Dodge Intrepid 6 cyl Front Wheel Drive Automatic 69,000 miles
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Well, fella's, I got a good one. I have a 2002 intrepid with the 3.5 SOHC, just shy of 70k miles. My check engine light came on (car ran fine at this point) and when scanned gave codes for defective oxygen sensors (upstream). I replaced both, and did the spark plugs while I was at it. The car only started running rough though! Double checked the sensors, and then even replaced the new ones! Looked on the internet for what else may be wrong. I was influenced to go ahead and replace the upper intake manifold gasket, but it was not the problem. Took the car to a mechanic who advised me to let him change the plugs (he claimed that the bosch plugs I used don't work as well as Champion plugs), and do a fuel system cleaning. It still ran rough. Put a can of fuel injector cleaner in it, still ran rough. The car will miss, stutter, and stumble (sometimes at a stop, sometimes while accelerating). Before allowing the first mechanic to start replacing fuel injectors, I got a second opinion. The second mechanic suggest that the computer needs to be flashed,and can only be done by the dealer. The problem there is that the last time I took the car to the dealer, they were unable to establish communication with the computer (this was when wal*mart destroyed my key trying to make a copy)..walmart refused to pay for the repair, and I am scared that it is coming back to bite my behind.....What can I do?

Check all fuses with a test light first, if the PCM wont communicate there is a problem that must be taken care of first.Sometimes the PCM is bad or like you were told needs to be flashed, but if it wont commm it could be a blown power fuse to the connector for the PCM, no promises. If all are ok, then off to the dealer for your new PCM, car has to communicate to be fixed

I took the car to the dealer today, and they reported no problems with attempting to communicate with the PCM, maybe it was just when they tried to program the BCM. They have suggested that the rear oxygen sensors need to be replaced (I only did the upstream). As far as I knew only the upstream sensors affected the fuel managment...what gives with them?

The "downstream" sensors measure catalyst efficiency, not much to do with mixture control. What were the exact codes they pulled from the PCM?

So, when I went out to the dealer to talk with them about what was going on. The last time them and I spoke they talked me in to doing the D.S. o2's because they said that since I was already going to have the cost of the diag. fee, that if I brought the new sensors in ( to make sure they were a matching pair with the U.S.o2's I already replaced ) they would install them for no additional cost. After they failed to call me friday evening as they told me they would earlier that afternoon (when I called them, because they forgot to call me) it was all the way till tuesday that I even heard from them. When I went up there tuesday morning the service advisor I had been speaking with all along shows me an o2 sensor off my car (the threads are twisted and broke), he then states he thinks whoever put it in cross-threaded it (it looked like the threaded portion got stretched to me). And then had to wait till wednesday for the service manager to get there. And now here I am with a car that is broke because of a repair I didn't want to do, and only did because the labor (I think the tech. didn't start the car for a bit before removing the sensor!) was free! And you can only guess how much that cat/header/downpipe cost with installation!

Have it taken to a muffler shop, they can weld in a new receptacle for the sensor and weld the old one shut.