PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

idle issues, no codes, would like some help

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Old Jul 31, 2012 | 09:01 PM
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Default idle issues, no codes, would like some help

The situation is one night I had the car ready to make a few runs. Put 5 gallons of 110 leaded in the car mixed with 91 rest of the tank. Car ran like a champ till it got down to about half a tank. I was unloading it off the trailer and had to get out to check clearance, while i got out to look all the sudden i noticed a big change in tone on the idle and it was idling very rough. The next day i took the car out and only when i would hit stop lights the car would load up sputter and run like garbage so bad i couldnt harldy drive it, eventually it would clean up and run fine.

Now since then i figured the leaded just killed the o2's. Its had new o2's put in, been through 4 tanks of gas, new fuel filter, has 58psi fuel pressure at the rail. Checked the primaries with a heat gun and are within 10 degrees of each other. The car now doesnt load up so bad, however at every stop light and slow accel to pull away it sputters and runs like crap until i hit about 2300 rpm then it clears up and runs fine.

I do have hptuners and am not very knowledgeable using it yet but have friends that are. We did some messing around with the car making a few adjustments with fuel in the main VE table that needed changed reset the fuel trims so as they would reset now that the o2's are fresh. Nothing is working and its very frustrating that it has this driveability issue. When we turned off closed loop at idle the car ran perfect every time from stops and slight accel. I've noticed that during a log the o2's are all over the place at idle on the lean side and set for tune around 14.7afr during normal driving and idle. The o2's sit in the upper 15's sometimes low 16s for afr and dont cross the 14.7 for almost 16 seconds or better. However during normal driving, the o2's are perfect and following each other exactly. Sorry for the long post but if any of you have an idea what i should look into i would appreciate it.
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