Loosen the jam nut first, then make ajustments. tighten jam nut and check again. sometimes when the jam nut is tightened, it messes with the ajustments you might make.
If that doesn't work get it somE viagra!
ive heard of that trick, giving your car viagra...i tried it and my car just perked up, shot right off the line, and got the job done in about 14.5 seconds.