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Stuck and need help... Bad idle with infamous P0171 code

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Stuck and need help... Bad idle with infamous P0171 code

Old 10-29-2018, 11:00 AM
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Stuck and need help... Bad idle with infamous P0171 code

So me and my dad run a transmission shop and we're not the best with electrical so I'm stuck. Already spent 70$ replacing.the damn boost intake sensor and 30$ on the evap purge after checking everything else off and researching. Didn't do nothing. A lil info first. . I bought my 07 lsj S/c cobalt needing a clutch and not knowing all the upgrades. From what he remember from previous seller and what he did The guy said has stage 3 exhaust which I checked and it does, it has cold air kit, all the poly mounts for the LSD manual, dual pass intake but gave me the intercooler to put on which I didn't. It's just my daily. Well the battery went bad and when I got it tested they said it was fine. Had a surge when I went to jump start it and it fried radio and projectors. Then after a few weeks of using jumper box to start it (because the battery just wouldn't hold enough overnight) I replaced both lights/rad and it was running fine. When I got new battery and held juice to not reset ecm it started having a wild idle. 700 rpm then up to 1400 and back down. Figured it was the throttle body so I did a careful cleaning which it was filthy. Along with replacing the air filter. I just did plugs too. Once I did that it got much worse nearly dying no matter what I did to move from a stop and sounding like a miss when around 2200-2400 rpmrange. Now back a month ago Everytime I clear codes or unhook battery for 10+ seconds it would reset whatever and run fine. No black or.white smoke coming coming out when accelerating and perfect idle until it catches it after 3 failed ignition cyles then id get a bank 1 O2 running lean. Also sometimes would say running rich?. But Now when I start it it just runs bad for most part. Sometimes does the idle fluctuations and almost always the missing sounds at mid rpm and as soon as I clear the lean p0171 code it comes right back instead of waiting a few days. Also now the check engine light will flash when I leave from a stop and shift second as I release clutch it stutters then the CEl light flashes.. so I once again went to shop to see what scanner may hopefully show and as I was sitting there idling CEl started flashing nonstop while just sounding like it was way off timing or not enough fuel. Scanned and this is what it showed for codes. Any and all help is appreciated I just have no idea what to do anymore Thanks, Harold

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Old 11-02-2018, 08:51 AM
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i would start by replacing the coolant temp sensor
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Old 11-02-2018, 04:46 PM
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Not meaning to steal the thread here, however I am having roughly the same issues with my 06 ss/sc. Basically the car surges during wot around 4-5k rpms horribly, it acts as if it's getting all the fuel but no air. I've cleaned the tb, new maf, new camshaft position sensor, new coolant temp sensor... nothing is fixing the issue. If I unhook the maf and hook it back up it runs great, I figured the maf that i had bought was defective but I recently bought another one from the dealership and nothing changed. Someone pls help, this has been an on-going issue for about a year now.

- 06 cobalt ss/sc
- Stage 1 pcm
- Headers, full zzp exhaust
- K&n cold air intake
- NGK Iridium plugs
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