1987 Plymouth Sundance

I have a problem with an '87 plymouth sundance that we can't figure out. It has a 2.2 4cyl engine with 180,000+ miles. We will be driving along, and all of a sudden we will experience a power loss, meaning that the RPM's will drop right off and it will try to stall. But it usually goes right back to normal. Now, lately, all of a sudden it is doing it more often in succession, and not recovering sometimes. Also the "power loss" light will sometimes come on. And it will also stall when you stop at a stop sign or red light unless you push it into neutral and rev it a little. It starts a little harder than it should and only stays running if you keep light pressure on the gas. Here is what we have done: distributor,pick-up coil, spark plugs and wires, regrounded the engine, checked out the fuel system (which is fine). checked tranny (auto) which is fine. We are at a loss and this stupid car is causing me to lose work..... I really need help fast!!! Thanks!