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Intermittent code 23 Oxygen Regulation

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Old 01-12-2018, 04:31 PM
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por4ever
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Default Intermittent code 23 Oxygen Regulation

Hi all. I recently picked up a 968. After I have been driving for a while I get the Check Engine light during steady cruise. If I let off the gas the light goes out after about 5 seconds. The code is a 2 23 intermittent oxygen regulation. A description I read for fault 23 talks about the oxygen regulator. Is that the O2 sensor? I don't get a code for an O2 fault. Is it the MAF? I don't get the code for that either.

When pulling away from a stop light I get knock. CEL does NOT show a knock sensor code. The plugs and fuel filter were replaced last week with no change. I have sprayed some MAF cleaner around different vacuum lines and connections including around the throttle body but no result. (Is MAF cleaner flammable enough to detect vacuum leaks?) But at idle the CEL is not lit so the leak may not exist at that time.

The car runs great otherwise. Feels like it has all the power it should. No stumbling even when I hear the knocking. Knock is not constant so I don't suspect rod knock. There is a very slight stumble while cruising on the highway but not while accelerating. That with the knocking makes me think I am lean but I can't find any leaks yet. Intermittent issues are the worst. Any ideas?
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Old 01-12-2018, 07:47 PM
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are the ignition components original? rotor, cap and wires?
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Old 01-13-2018, 01:32 AM
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I looked through the records the PO gave me. I don't see a bill for those. When I had the fuel filter and spark plugs replaced they checked and cleaned the cap and rotor. He said they were dirty but not worn. I did notice on the way home from work today if I keep a constant speed the CEl comes on. If I accelerate or decelerate the light will go out until I get to a constant speed again. I just received the throttle body reseal kit from Paragon. That will be done this Sunday.
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Old 01-13-2018, 09:42 AM
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reseal kits may not be compatible with the 968.

start your car n a dark place with the hood up to see if you see sparks.

oem plugs should have three grounding electrodes.
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Old 01-13-2018, 11:26 AM
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The TB kit I bought does say it works with S2 and 968 but I'll compare parts that come off with the ones I am replacing. I'll contact the shop on Monday if the invoice doesn't say to confirm what plugs they used. This shop has been around forever so I feel confident in their work. I don't think the plug wires were checked so that's an idea.
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Old 01-13-2018, 11:52 AM
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Vacuum leak. Find it with a smoke tester.
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Old 01-13-2018, 11:53 AM
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I see where B ruce has one now but not Jason.
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Old 01-15-2018, 10:34 AM
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On the ignition wires..like the other poster said, find a dark spot..dusk is good, and use a spray bottle with some water in it..spray it on the wires..while the engine is running....if they are bad, you'll see the electrical display.
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Old 01-15-2018, 06:43 PM
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On the 968, you might remove the vanity cover to get to the two plug wire mounts screwed to the fuel rail cover. That is where mine had failed.


If the ignition components are 20+ years old, even if they 'look' ok, I would change them.
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Old 01-17-2018, 08:32 PM
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I re sealed the throttle body this weekend. CEL still lights while at steady peddle position. I did find that if you repeat the procedure to pull the code with the gas peddle other codes will display. Second code is for TPS. I should have that by tomorrow. The 968 TPS is not just a switch as in the 944. It's a potentiometer. I can't find resistance values for it anywhere but I'll compare them before I put the new one in.
I'll see if the new TPS fixes anything and troubleshoot from there.
Does anyone have the 968 shop manuals in pdf? The link on the archived Cannels site does not work for me.
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