ramp runs

is it normal and if so, why does the graph not increase smoothly why is there drop outs slightly as the rpm increases usually ramp runs increase in a smooth linear way that ive noticed

thank you

Since I don't know what particular graph or issue you are looking at, this is all a guess...

The X-axis of a graph will usually be either speed or time. If you have a graph of Engine Speed (RPM) vs. speed or time, it should be a straight line, however if there were an error in reading the Engine Speed (crank sensor noise, bad wire, etc), then however the Engine Speed is detected might show a lower value (or no value) for a short period.

Now if the X-axis of the graph is Engine Speed (RPM), then missing torque/power data might be due to some other issue with the dyno, or the tune (perhaps there was a huge drop in torque due to an ignition / fuel cut).

I'm afraid you'll need to show us the graph you are talking about.