Erratic idle PLUS jerk/hesitation while cruising...

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Jan 28, 2010 | 04:48 PM

#21

deanfootlong

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From: san diego

if its been happening all the time; at idle you probably have a lean spot. it'll hunt up and down between cells trying to correct itself. and while driving; you probably have a lean spot there as well. try to take note of what rpm and vacuum you are at when it hesitates. then change the values in that cell on your map until it stabilizes. most times its a lean spot.

Jan 28, 2010 | 05:38 PM

#22

jonnylaw

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From: Meifumado

Quote:

Originally Posted by 1985zcar

I've got this same issue...I'm HKS FCon + GReddy TT...I actually have O2 sensor faults...6 of them. Now I highly doubt all my O2 sensors are failed...possibly the fault was set once upon a time and is still causing issues? I need to get the fault cleared and see if it comes back...but this weekend I'll take a look and see if I find any other things wrong.

Basically, under heavy throttle I have no issues at all, but idle sometimes bounces up and down, and while cruising with barely any throttle I'll get random hesitations.

Also, my wideband reads AFRs in the mid 14s while cruising, 12s in boost, so I'm pretty sure I'm fine on that.

Has anyone found a for sure cause of this?

I have been having similar problems (idle surge), but only one code-p1281-Af Sensor 1 bank 2. Replaced this sensor under warranty and the code came on again, also still experiencing idle jumpung. So I'm not sure if its the sensor itself--could be the harness/heater/short or open ciruit, could be in the tune if the AFR deviates too much from what the ecm expects. Also need to check for vacuum leak, clean throttle body, fouled plugs, clogged injectors, etc. I have HKS SC with fcon vpro and uprev reflash btw.

Jan 28, 2010 | 10:17 PM

#23

1985zcar

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From: Mill Creek, WA

Yeah I'm gonna do some work on Saturday, take a look at the 02S wiring, and clear the faults, see what comes back, etc.

I'll let you guys know if I find anything.