i went to the shop today, helped them install my hrc 3" downpipe and helped them reinstall the vacuum hoses and FPR. everything runs, the car works fine, except for one problem (not counting the ridiculous loud exhaust because the hrc downpipe doesnt bolt to the cat).
the car cranks up, idles at 3000 for about 10 seconds, then will go down to 1000 rpm idle, but it will fluctuate between 1000 and 1500 constantly while the car is running. i ran the pcm codes and got 12, 15, 21, and 25. the only important ones there are the 21 and 25. i guess the speedometer cable is defective or not connected (code 15). the code 21, for the 02 sensor is a code for the upstream sensor on the downpipe, its brand new i just bought it today. so the only thing left is the idle control sensor...what do i need to do to check this sensor, is there a writeup or a previous post that i a mmissing? i will take a video clip as soon as a can and see if i can post itif necessary. i'm so close to having this thing fixed, any suggestions on how to fix the idle problem will be greatly appreciated.
thanks

edit: is there any significance to the part of the error code that says "stays at center?" the o2 sensor code says "upsream h02 stays at center." is that just another way to say the 02 sensor isnt reading properly or is defective?

1995 Eclipse GS - HRC Stage 2 - Retired.
2004 350z Enthusiast / 2008 Nissan Versa SL

If I'm not mistaken, the ECU also uses the signal from the speedo to adjust idle. (As in, to let the ECU know if the car is moving or not.) And, while I'm not really sure what is causing your idle issues here, I have to say it's good to see you posting regularly again around here. Seems to me that you were relatively quiet for most of the past year or so. Just an observation.

Good luck. Those little idle issues are always a PITA imo.

Yeah that means the o2 sensor is probably broken. Always the chance the o2 sensor we dropped before it got to you. They are ceramic and can break easily.

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four nails four corners four riders and four horses

yeah the major reason i wasnt here for the past year is that i havent had access to my car since the middle of july...it's been in the shop THAT long. can anyone confirm that the speedometer controls idle? that could certainly be the problem. if not, does the front 02 sensor reading affect idle?

1995 Eclipse GS - HRC Stage 2 - Retired.
2004 350z Enthusiast / 2008 Nissan Versa SL