Yes, the mystery continues because the villains are still working in your car.

I would not recommend gasoline and plastic bags. They will probably melt. I recommend pint size glass jars with lids. Punch a hole in the top with an extra hole for a vent to let air out as the gas goes in or make the injector hole a smidgen loose. To hold them use tape, rubber bands, wire ties or bailing wire, what ever will work to attach them.

Your compression is good so that rules out a reason for the gas not burning properly across the engine. You supposedly have good spark and you checked the timing. This puts those things aside as the engine should be firing across all the cylinders.

You changed out the AMM and it was fixed or at least better. Now we have the in and outs covered, I think.

You changed out working injectors with more working injectors. Ah, ha we have a clue.

The first injectors were working as leaking into all the cylinders or the cold start injector was a villain. You pull him out and lock him up but the crime continues. Ah, ha another clue I think.

The newer injectors are doing the same as before except for one. Why is that, I have to ask myself, or you, as it would be better since you are doing the work.

We have seven out nine injectors spraying gas when they are suppose too or they are all leaking all the time. Two injectors are not spraying. One is not in the car; we locked it up in a box on the bench! The other one is number three.

We are back, to my earlier post, to where I wanted you to lay the suckers out and see if they leaked. Why should they, as in all, leak? I can only come up with two reasons.

Villain number one is they are all powering up except number three. The injectors are grounding regardless of what the ECU wants to do. They ground is pairs, I think, so the one might be is out of the loop like a bad connector or harness!

Villain number two is, they all are getting trash in them. A filter has blown through and garbage has hit everything! The garbage is as filter media substances and some fine metal from gas hose nozzles, rust, grime or disintegrating pump rollers.

With the jars on you can test for everything and you will not be pouring gas in to the oil again. Use big enough jars and you can flush the system if need be.

Hope I wrote this in a way that it will “play out” favorably for you.
Phil