keith;
You must get the mixture right. Especially with your 2x4. Their about as high maintenance an a 20 yr old super model.
dont leave it rich; washes down cyl's. fouls plugs, pollutes
oil.
Two ways to get the F/A right; one expensive-one cheap.
go to good dyno guy and have him calibrate/rejet carb.
or weld in a oxygen sensor bung in one header pipe and install a $15 O2 sensor and put your digital multimeter on it and read directly the F/A mixture. This way you can calibrate idle, midrange, WTO percisely. Works like a charm. Hint: where does your FI computer gets it's dynamic F/A input.
If you need any additional info; or the O2 voltage output curve; give me a call.
gn