Hi Mary,

I will first off tell you that all I have are the 240 model vehicles and do not profess that what I’m about to say will have a lot of impact on getting your car straightened out but here goes.

First off moving the distributor around will hardly change the timing but it can have a slight effect on the duration of spark in transit from the rotor button to connect up the spark plug wires.
The end of the rotor button sweeps in an arc in front of each terminal in the distributor cap. So ideally you want the tip, that is rather wide to be in the area of any terminal to work correctly.
The timing of the engine is controlled solely by a Crank Position Sensor and any adjustment by the ECU program modes.

Having bad spark plugs wires is like having an expensive stereo amplifier with frayed wiring to the speakers. Lot of distortion can happen to complete failur of a speaker or in this case a spark plug.
A tune up is always a base line of good maintenance.

As far as the injectors it’s hard to believe that all four will go bad at once in the first place.
Improper fuel delivery can cause that.
Water or dirt in the fuel is the same, let alone the pumping of it.
According to another poster is talking about an accumulator device.
A fuel quantity test might be in order or a filter change if you got bad fuel in the car.
In most cases, on the 240s, have very large fuel filters that suppress pulsations today.
Accumulators started out being used on the more mechanical “Continuous injection systems” long before the nineties cars.
They appeared early on and to be a little bit of an engineering overkill. Fuel injection and emissions kept the fine tuning going.

I would suggest only having them tested or cleaned, if you have suspicions that there was contamination.
I want to say that pulling off the injectors clips to experience a change is a nice idea but it shouldn’t be concluded that an engine can only run on one injector.
So he is not correct!
I hardly think its conclusive, either way, in that he is messing with something more electrically responsible.
All the injectors share power from one source and grounded individually by the ECU.
He might have scared the gremlin but in no way did he find him.

I feel that maybe you need a “ignition tuning service” done to get a base line standing on the cylinders firing well.
I have a problem with the exhaust system diagnostics if the cars engine running condition is a questionable.

Have you ever checked out the exhaust flow from the tailpipe?
You should have more flow as the engine speed increases above idle. I use my pants legs to feel the flow outward and hold it very closely to see if it sucks back or pops the fabric at times.
I test for exhaust valve functions as it should stay steadily outward.

I know it’s hard to get a baseline with so many people dipping their hands under the hood for a minute or two for free.
It’s not healthy for the car or the owner as both get confused results.

You appear quite mechanical in your thinking and whatever the issue is, it needs some steady steps of procedures, as if learning from a textbook in school.
Do you have any shop service manuals for doing car repairs?
The best mechanic is you, as you have an incentive.

Phil