2008 LS3 Corvette M6, BTR 225/238 cam 50k miles E50
Fuel trims have been tuned in VVE and combination VVE MAF.
I have a rapid timing oscillation under light load, level surface driving, in the 800-1,300 RPM range where timing jumps between 35 and 5 degrees many times in one second. I've had this issue with other aftermarket LS cam swaps. In the past I attributed the problem to reversion due to valve overlap but I noticed recently the timing swinging wildly and that swinging is what's causing the rapid jerking of the car. I'd gladly pay for someone's assistance in resolving this issue.
Included is a troubleshooting tune and log with all of the timing everywhere set at 24 degrees with the exception of idle under speed and final minimum Spark. Even with a timing lock at 24 degrees why is the ECM dropping to 5 degrees?
I have a second troubleshooting tune and log with final minimum spark set at 24 that does prevent the timing from dipping down to 5 degrees but the oscillation is still there.
This is a manual transmission and this jerking issue is very annoying in my driveway and in parking lots so please don't criticize the circumstances of the log it's just an example