so ive been getting etuned lately and for the past few calibrations my car has been leaning out on very light throttle lets say 5% throttle and cruising on the highway. itll lean out to 15-16 and start making popping noises.usually happens when the cars warmed up and has been driving for a bit. my tuner and i are having a hard time figuring this out. he is a vey credible tuner so i dont doubt his skills. just very stumped. even at idle itll randomly go lean time to time.Wot is perfect tho.even normal part throttle city driving gets very choppy at times. had my aem sent out to aem to get it fixed a while back so the box should be fine. i am supercharged at the moment walbro pump, rewired,10psi vortech system,ngk BKR8EIX plugs, omni 3bar map tuned on aem ems 2. any ideas?

 

Can you post ur datalog tables?

 

I can send you the map. Email?

 

Are you running 02 feedback in closed loop like the stock ecu does? If so, the sensor may be going bad.

 

The sensor is fairly new. Less than 3k miles on it. O2 feed back was turned off and had the same issue.

 

I have similar issues with very light "transient throttle" settings as Haltech calls it. I fully believe that with a few more hours of street tuning I could work it out in the tune settings. Barely cracking open the throttle body causes a sizeable influx of air since our SC's are always pumping air while driving. The tune has to account for this by enriching a good amount right when a transient throttle occurrence happens. It wouldn't explain your idle issues though.

 

could be an injector issue.

 

Tuner believes it could be the pnp harness for the id injectors. But i dont wanna hardwire them because i have to switch back to stock injectors fpr state inspection. Any alternatives?

 

Leave your stock plugs there but just tap into the wires with the ID plugs. That way you essentially have two plugs coming off the same set of wires. Wrap some tape around the stock plugs for now, and when it comes time for state inspection put the stock injectors back in, remove tape, plug stock plugs into injectors and go.

I feel like if it were the injectors/harnesses you would feel the car stumble a good amount. Do you feel the car shudder and noticeably miss when this lean condition happens? When one of my injector harnesses was acting up the car would sound like a Subaru and start shaking/shuddering pretty bad. A bad injector harness connection wouldn't cause just a single miss, it would be multiple in a row, or at least mine were.

 

I would think if it was the harness it would misfire all the time. But its only after ive driven the car for 25 minutes or so. Car jjust breaks up and pops at very low throttle.