Lau Ho Ming

Hi Everyone. I have an 2003 JDM RX8 MT.
Actually I have this jerking acceleration problem at low gear since I bought this car about 4 months ago.
The problem usually occurs when I try to accelerate at low gear low speed. The acceleration will be smoother if I clutch in and let off slowly while appling throttle.
First I think it is because of Rotary Engine being no torque. But people said it is not supposed to behave like this.
Sometimes if I try to accelerate from 1st gear 2000rpm, it will keep jerking and bucking all the way to 6000rpm like someone is having sex violently in my car.

Jerking and bucking can only be felt if I try to accelerate from low gear low rpm with certain throttle pedal pressure without pressing in the clutch.

My car is mostly stock except BHR coils ,1.5way LSD. Some unknown racing clutch(Maybe lightweight flywheel?) by previous owners.

I cleaned the Throttle Body, Changed to BHR Coils, changed the new spark plugs, wires. Engine Compression is fine. Still can't figure out the problem.

And Recently, I bought a Tactrix and MazdaEdit to mask the DTC code for BHR Coils and change the omp rate,ignition coil dwell, unlock 180kph etc...and I used the logging function to log the ecu data while I try to reproduce the jerking issue.

And here's what I found out. The acceleration pedal position seems to fluctuating violently when that bucking problem happens. Does that means I have a bad acceleration pedal sending out bad data and caused everything to fluctuate as well?

Thanks.

Acceleration Pedal Position


RPM


Engine Load


MAF


Throttle Position Sensor