To check the throttle position sensor, leave it's connector on. Take a volt meter, connect it's negative lead to "ground" some where on the manifold, block or a bracket. Put a pin, large needle, or heavey peice of wire into the center connector at the TPS so you will have a place to connect the positive meter lead. Maybe then end of your meter lead is long/thin enough to put directly into the center pin at the connector of the TPS. Be careful not to be too rough to avoid any damage to the connector or pin.
If all is well you should see some thing between .2 and .9 volts on the meter. You might have to move your makeshift pin around a bit to make a good connection to see the voltage. Now if you move the throttle open slowly it should go slowly up to 3.9-4.5 volts. It should smootly increase and decrease as you open/close the throttle. It you see it jump any time quickly or wildly, then its probably bad.
You say your trouble starts at 1700 rpm. Does it continue at rpms above that or does it smooth out again once you pass that rpm range. If it continues at higher rpms and the TPS checks ok, then it could be other problems like fuel starvation caused by... old fuel filter, bad plenum gasket (losing oil maybe a sign), worn distributor coil, worn fuel injectors, leaking fuel pressure regulator, busted catalytic converter partially blocked inside. Even transmission problems can case some performance issues. Is the tranny fluid level ok? Since you say the timing is all over the place, it might also be the crankshaft position sensor. And on an older Jeep (I'm guessing we're talking about your 1993?), it could be a combination of more than one of these things adding together. Also have you looked at this wire rerouting diagram. It made a difference in my 1994 Jeep.....