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Discussion Starter #1
Hi im Jose, im new to this site and wanted to see if anyone found a solution to this problem. I have a 2007 cobalt ss s/c, just install a 2.1L gen3 gridle block, neutral balance shafts, 4340 rods, je pistons 9:5:1 ratio, port and polished head with stage2 cams, #78 valve springs and retainers, ati balancer, Zzp3" intake, zzp long tubes, hypersingle clutch stage3, 3" exhaust, tvs 1320 supercharger on 2.8 pulley on new tune.

This is my problem, at idle it jumps from 500-1500 rpms. At random times it falls to 10 afr, thenwants to stall out. I replaced map, and ignition coils, spark plugs, injector harness, also replaced o2 sensors. I checked for short to ground on maf and resistance. Cant seem to figure it out, if any one had a problem like this please help!
 

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Discussion Starter #3
I have the ls4 tb and had a spare, swapped it out and still acts up. I ordered stock lsj tb cuz im tired of a touchy throttle. I got tuned by laser (kendall) from houston tx, he had tuned my car and it was running mean. It was acting up before he tuned it and it was for rear o2 sensor cuz it was deleted, he turned off codes but now check engine light blinks for a while then turns off after car stops running rich, im thinking the computer went to crap.
 

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Levee
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Have you data logged it?
 

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Discussion Starter #7
No I havent data logged it with hpt, all I have to go by is my intercepter and obd2 scanner with datalog freeze frame. I just checked today and my throttle percent is not working, just cleaned it and reinstalled rear o2 sensor, still runs like crap tb percent is not working still
 

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Discussion Starter #9
Yea it might be, but it was acting up before, and I had swapped tb lk two weeks ago and still was acting up. I got an lsj tb but Im not tuned fof it. I tri ed d to put it on and my balt was acting a little better but still wanted to stall.... I wish I had a tuner closer to victoria tx
 

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Discussion Starter #11
Yea but all the codes that were turned off I think those are the ones that blink on and off. Other than that no. I did have a code for fuel pump like two weeks ago then turned off.
 

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Levee
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Codes that are disabled wont show anything, not even blinks. And you should be tuned for an lsj tb as that is what came with your car. You need a log in real time ao you can watch your tps signal and voltage. That can very well be your problem, but you need to log it to be sure, unless you just replace it.
 

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Discussion Starter #13 (Edited)
Ok so I just replaced the mass air flow and my running rich issue is gone, but yea I need to swap back to my lsj tb. I also replaced knock, and crank sensor just for the heck of it. My original crank sensor was scuffed up? But car seems good but check engine light still blinks, but hopefully soon I get my stock tb on. I got one more issue im running meth/water but my iats still get to 160. I jumped my relay to see if ic pump is working and still is, I pulled meth nozzle and applied boost and pump sprays, any ideas?
 

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Levee
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What mixture are you running? How much are you running? What are the IAT's without meth?

And for the CEL, it may just be a knock indicator if it's just blinking. I tuned my CEL light to blink when I have knock on my evo.
 

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Discussion Starter #15
Im running 10%meth 90% water, im at 12.8 afr, without meth my iats hit lk 190. But two weeks ago it was at 135 iat at wot. Also im running a 7gph nozzle
 
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