You might have a broken rubber vacuum line or stuck EGR valve that could cause the intake manifold pressure to be too low. You might also have a broken device that uses vacuum (for example, a broken membrane in a dashpot.
The problem is not likely caused by the transmission. However, if something is seizing the engine, it is possible (for example, the torque converter might be seizing, but, this is a very rare condition).
The problem is not likely caused by clogged fuel injectors because they would have more problems when there is more fuel demand (at high RPM, not idle).
"Richard A" could be right about bad/dirty spark plugs. Or, perhaps bad spark plug wires, or bad coil module (cross sparking and shorting). A stuck throttle could also drop engine vacuum (as "Richard A" suggested).
Spark plug wires should be changed every 50,000 miles. Spark plugs can often go 100,000 miles, though they wear wider, and that might require re-gapping. Furthermore, plugs can also foul if the rings leak oil (you have an older car with a lot of mileage).
Check the plugs, and clean the throttle body with a carburetor cleaner or brake cleaner. You might want to get a fuel injector cleaner as well.
Nothing to do with what richard said. It's clearly transmission related. The stuff he mentioned could help on making it harder to stall out, but there's still the problem.
without any doubt the problem is with your transmission most of the times power is not enough or sometimes transmission system might need a real service.
Fuel injectors, filter. Men tend to start with the most expensive.
I have a 2003 Ford Explorer with over 180k miles on it. I bought this car a year ago, and I haven't had any problems with it until now. Every time I put it in park it sounds like it going to cut off. Yesterday it finally cut off by itself. It starts up and runs average, however it is a little shaky while sitting at a traffic light. I am not familiar at all with these kind of issues and would appreciate any suggestions as to what can be causing this.
