So if it's not in the steering wheel at all, it's not tie rods or front suspension parts, most likely. If you're feeling it in the wheel but also all over, could be front suspension parts or tie rods. Hard to say what, really, over the internet. Saying it's when you're on the gas, but not off the gas, it sort of tells me to start with the rear half. Look at your trans mount (look for tears in the rubber), and then check your shocks. May need replacing. May need a rebalance on the driveshaft. Could just need 2deg shims to correct your pinion angle. Start with the cheapest stuff and go from there.
