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Old 03-30-2009, 10:53 AM   #1
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Bad O2 sensor kill HP?

I have a bad O2 sensor and when the engine is cold it feels like the car is going into limp mode in the lower rpms and wont go anywhere. Could a bad O2 sensor pull horsepower from the engine? Kind of like going into 'prevent' mode or something?

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Old 03-30-2009, 12:16 PM   #2
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I doubt that a bad 02 sensor would rob the car of HP. My 02 is shot and needs replacement. I have had to drive it to the mechanic's and to work and it still feels normal (though I've not redlined it or pushed it hard). It would have been in 'prevent' mode already for me I'm sure. Might be something else, but I don't know what. Perhaps someone else will chime in.
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Old 03-30-2009, 03:06 PM   #3
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A bad O2 sensor can keep the car's dme in closed loop operation which keeps the mixture richer and you'll be down on power because the car selects pre-set fuel maps which do not vary since there's no sensor to send realtime conditions to the dme.

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Old 03-31-2009, 04:06 PM   #4
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Thanks for the info Lil Bastard. I just got mine fixed and it felt sluggish at first but at the end of the drive it started getting peppier. I have a 3.6L in there by the way.
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Old 05-04-2009, 08:09 PM   #5
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seems a fine thread to hijack... I cleared some codes the other day... O2 sensors are on their way and just wanted to get rid of that light. I specifically thought to myself on the way out of the neighborhood "this car couldn't possibly be running any better" then i cleared the codes... ever since, right about variocam kick in the car seems to bog. I hope this is the car learning itself back, the code has already returned (driven 100+ miles) but it hasnt seemed to work itself out. Now i am scared to death the clutch is slipping if the O2s dont solve the issue. Is this normal as 02s go out or as codes are reset? i used a OBDII not the battery trick. Any help would be appreciated, i'm not excited about springing for a clutch right now.
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Old 05-05-2009, 06:15 AM   #6
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It could be a bad O2 sensor...OR it could be an O2 sensor reporting another problem. What error codes are you getting?
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Old 05-05-2009, 07:56 AM   #7
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JAckelfox that happen to me too, right when you think the power is gonna kick in it felt like it died, for me it was my intake not getting enough air due to me using a boxster MAF housing on the 996 motor. Using a 996 housing fixed it right up.

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