Idle/O2 sensor/TB Problems?! [Archive] - Forum


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10-30-2005, 10:32 AM
I've got a very strange problem with symptoms all across the board.

My mods that might might matter for this
WAI, 62mm throttle body, Pacesetter header, flowmaster 2.5" exhaust, but still the stock cat.

1) When you first turn it on, there's a high idle ~1300, which will come down to 900 pretty quickly. Then it goes wonky and dips from 900 to 600 three or four times and sounds for all the world like it's going to stall. Then it's fine. If you start driving before this happens, it will surge while you're driving.

2) My "Trac Off" light comes on intermittantly, for no apparent reason whatsoever, and it will no longer respond to pushing the button. This is appariently somehow related to my oxygen sensor, or I am led to believe. I recently had my oxygen sensor replaced for a similar set of symptoms, but that was only about 1.5 months ago. Something is going on thats fouling my o2 sensor but i have no idea what it could be. The "Trac Off" nonsense is starting again.

3) My exhaust tips are completely lined with an oily/sooty residue.

All regular maintenence is being performed on this, and the car seems to run fine on it. It's also go very low miles and is in good condition otherwise

Any ideas are welcome, but i feel as though this is going to lead to something expensive unless it's fixed.


10-30-2005, 10:49 AM
Which O2 sensor did you have replaced? There are two one before the cat and one after. The one before is the more important of the two, also how are you lead to believe that your TRAC light has anything to do with your O2 sensor? Third my car does the same when I start it up, excluding the almost stalling part, it wil start around 1000 to 1300 rpms then drop pretty quickly to normal idle.

It sounds like a fuel problem if the car is surging, but like I said if you haven't then replace the O2 sensor before the cat and see if that helps.

10-30-2005, 11:06 AM
The onne that's before the cat, i believe.

around the middle of september, the same thing was happening (then i did not have the TB), so i took it to garage (cause i was about to drive 1200 miles in a weekend) and they for whatever reason said the two problems were related. And after they replaced the o2 sensor, the trac light problem cleared up but the surging problem didn't

I'm reluctant to replace the o2 sensor again until i find out why it's fouling to begin with, otherwise i'll be replacing it every 2 months forever.

10-30-2005, 02:43 PM
I would say take it to a dealer have have them look at it. Are you throwing any SES lights?? My dealer only charges about $30 to diagnose a car ... so it is a thought.