The Nissan Path

I'm new to the forums, and new to the world of being my own mechanic so please bear with me.

The pathfinder I own is having a ruff idle while in gear after warming up. It bucks and jumps as low as 700 rpm, and will die. The second I go into neutral Rpms go back up to a steady 1000. Park is also safe from ruff idle. When driving, while accelerating, the car jerks and jumps, at this the rpm needle just drops and bounces back to normal quickly. Now here is where we go from here. I have thrown parts and time and curse words at this and 600$ to a mechanic.
This is the list of parts changed in order.
Fuel Pump
Distributor Cap
Drivers Side O2 sensors
All Spark plugs and Harness.
Knock Sensor
Crank Shaft Position Sensor
Rear Main seal
MAP Sensor
PCV
Also until we started I never knew that someone replaced the orgional intake tube with some aluminium craps and put a breather on the hose to the valve covers and plugged the other hose that goes under the throttle body. I bought a whole OEM intake box MAF sensor and duct for 150.
I did not relocate the knock sensor, but I changed valve cover gaskets and stopped a leak on the right bank, found no vacuum leaks, idle air control valve got cleaned and tested, EGR Valve was in good working order. The mechanic I brought it to basically told me he's out of his realm, he mostly does Chevy and Ford's being in the south, and said his diagnostic tool isn't as fine as other shops or the dealer.
So I'm thinking it might be a bad ECU, giving scrappy air to fuel ratios and causing bad shifts in the transmission for the surging. But I'm close approaching the $3,000 mark on a KBB value of 5k. I can not afford another vehicle, unless this car runs without these problems I can't sell it, and I am almost going to say I want to drive her off a cliff. Please help.

I bet it's a vacuum line either cracked or disconnected.

That's what we thought at first before changing anything, but 3 carb cleaner cans later and no jump in rpms we moved on to other possible solutions.

It could be a bad distributor, which wouldn't be a first. I would want to see what the spark patterns look like using an oscilloscope, but you'll probably have to take it to a shop to have that done.

I changed the cap but it didn't change anything. I made sure all the spark plugs were in proper order. The distributor could be bad, but it dosent have a hard start, squealing, or any syymptoms other than rough idle and surging while driving. Odd is that throught the day, it gets worse and worse. It will start out just ruff idle when stopped, then progress to drops in Rpms and hesitations while accelerating. Final progress is it will die if you take your foot off of the pedal at all. It is going to the dealer next month. I do have a code for P1444 but that could not possibly cause this issue I don't believe.

"Surging" is often caused by a lean condition. Did you replace the fuel filter, which is near the rear axle? And even though the fuel pump is new, it wouldn't hurt to confirm proper fuel pressure as I have come across bad "new" pumps. Otherwise, it would be best to get a scan tool to look at the ECM datastream info.

Answer has been solved. The control module inside the distributor was going bad. When it heated up it stopped working and sent scattered signals. Thanks for all the suggestions guys. Now to pay the piper, $787 to the dealer for diagnostic and part and labor.