Hi there. How is everybody?

Monday i had a o2 sensor replaced on my wagon because the engine light came on, also the idling was going up and down at times. There were two or three different codes my mechanic said came up when they did a diagnostic.Sorry but i dont't have the codes on hand but i will post them when i get home. If i am at a stoplight, the car would be idling normal but sometimes feels as if it was going to shut off and the engine light would come on then go off.The car never would actually shut off just felt like it. This would only happen after the car is warmed up and i've been driving for a bit. i call myself looking for a vacuum leak somewhere but have not found one. How can one check for a vacuum leaks at home? Maybe i was not looking in the right places. My mechanic did say to unplug the cpu on the pass. side kick panel for about twenty minutes or so to see if it would reset itself. Anymore ideas on curing this ailment is as always appreciated. thx. B

An easier way to reset the computer that I learned on this site is to disconnect your negative battery terminal for about 20 seconds. This will completely reset the computer and the check engine codes. Then read the codes if they appear. Turn car power on, find the tester on the driver's fender, pull the top off of the little 3 inch rectangular box and then put the attached plug into socket 2, push the button for one second and read the code. then push the button again for another second, keep repeating until the same codes keep appearing. Search on Brickboard for "2.4 codes" and read the chart for the explanation.
To reset the codes, hold down the button for five seconds then the led light will stay on, then hold the button down for another five seconds, the light will go off and your codes are cleared. To make sure the codes are cleared, press the button for one more second and see if the code is 1-1-1, that means all clear. Good luck!
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1990 240- 230K- VX cam, springs, bilstiens, spt exh, euro lamps-turbo whls

The only down side to resetting the computer by disconnecting the battery is that since the LH system is adaptive, it may run rough for a while until it "relearns" by acquiring data from the sensors and making adjustments. That can be done by driving the car for about a half an hour or so. It's a good idea if you changes things like the AMM, ECT, etc., but keep in mind that the car may run rough when it is initially restarted. You'll also have to reset your radio code.

This is something I posted in response to someone else's problem a while ago that may help you:

I have a 93 which had the same problem, plus a part throtle miss at cruise. I've developed a kind of check list approach that I'll share. From my investigation, an idle problem can come from four possible sources: (1) vacuum leaks, (2) ignition/electrical problems,(3)fuel delivery problems, and (4) sensors/ECU/AMM problems. I solved my problem through the process of elimination by checking the four areas in the above order, which starts from easiest and/or cheapest to hardest and most expensive. I first checked for vacuum leaks. Pay particular attention to the intake manifold and the molded hose from the flame trap to the breather box, below the intake manifold, and the lines to and from the idle air controller (IAC). While you're at it, check the hard plastic lines going from the intake manifold to the charcoal cannister below the right front fender. Mine were bad, but this didn't solve the problem. I used both the soapy water method and the propane method. Don't use chemicals which could damage the O2 sensor. I then checked the ignition, and did the same thing you did (plugs wires, rotor, cap), plus I cleaned with electrical contact cleaner (CRC from parts store) all the electrical connections and applied dielectrical grease (but NOT on the 02 sensor connections). Also, check for proper grounds, especially on the fuel rail, and check the large-amp fuses on the + battery terminal. Sometimes these fuses can become burned, but still not blow. Next, I checked the various sensors. The first one was the engine coolant temperature sensor (ECT), which is next to the knock sensor under the intake manifold. You can suspend it in a bath of water and check the resistance to see if it is in spec. However, make sure you get the chart that's correct for your car. I believe the one in Bentley is for the earlier, blue-headed ECT. Mine turned out to be out of spec, but this didn't solve the problem. I also checked the throttle switch as per the Bentley procedure and adjusted it, just to be sure. A lot of folks recommend cleaning the IAC and I did this (even swapped in a new one), but that didn't help me. If you suspect a bad one, there's a neat trick that was posted here to test it by swapping a gate valve and adjusting it for a constant idle. I next checked the fuel delivery system by checking the running and residual fuel pressure as per the Bentley procedure. I also removed the
injectors and cleaned them using the Ponte method of using a battery charger, backup light bulb, and compressor, but be careful this is dangerous. I cleaned the throttle body and used a new gasket (also a good time to check the operation of the throttle switch). Lastly, as everything checked out I swapped in a rebuilt AMM and cured the problem. From what I've read, these usually fail in a
no-start mode, but mine must've been the exception. When I think back on it, my problem was intermittant, so maybe this was a give away. My 93 still has a slightly rough idle when warming up, but having a working thermostatically controlled flapper valve seems to help (I differ on this with most
others). Pls post how you eventually find your cure.