I've been battling some strange misfire problems that are creating a lean condition on my car (at least, my wideband is showing lean...like 15.5-16.0 at idle). In a nutshell, I'm showing misfire counts usually in the single digits but sometimes as high as 10 or 12 at idle or very low rpms (under 2000), but they seem to disappear as soon as I put the engine under a load (driving around). As soon as I slow down at a light or stop sign, the misfire counts start popping up again. Also, if I put the trans in neutral and try to hold the rpms around 1500 or so, I get a slight surge...maybe 100rpms or so.
The engine is a stock internal LS1 that I just did a D1SC build on. We have reverted the tune back to a safe base tune with the OEM injectors (I had a base tune for 60lb injectors from Steve @ Frost) and the symptoms are better, but still there. The strangest part is that if I disconnect the O2 sensors and the MAF, the engine idles and revs perfectly with no misfires whatsoever. O2 sensors are brand new, and I have double and triple checked all ignition components as well as searching for vacuum leaks and ground issues. I even swapped MAFs and throttle bodies, but to no avail.
I am ready to set this thing on fire and collect the insurance money. I would really appreciate any insight or suggestions you guys might be able to give me on this one. I've attached my misfire config and my last drivelog if anyone has time to take a look.
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