MS45.1 Torque Tables Affected by Diff Ratio

[ddavies564]

Hello, I have a 2004 ZHP coupe and been having a hard time with the cars drive ability/throttle response. Drivability wise the car is very jerky. At low rpms the car surges and studders quite a bit until 2500 rpm the throttle response is smooth and consistent feeling. Consistently, at about 1500 rpm a low throttle the car studders/cuts very hard, makes the whole car bounce back and forth, then will just continue on. RPMs drop about 300-400 at the time of the studder and the MPG gauge will dip for a sec. The car also seems to have a lag when reapplying the throttle after decelerating. The car is a 6 mt and is new to me, no prior history on the car, I rebuild the whole car. I've performed tons of maintenance on the car trying to figure this out the following has been done: Plugs, coils, cleaned injectors, CCV, Vanos, ECU updates, throttle pedal, Throttle body, engine harness, ICV. Fuels trims are all under 2%. The car runs flawless otherwise under heavy throttle or higher rpm. I've ran out of things to try but was curious as I'm running a 3.64 diff ratio rather than the stock 3.07 diff, I'm wondering if this can cause trouble with the torque tables in the ecu tune. Any feedback on this would be appreciated! Thank you.