OK.. here is what it is not...
 

not the WUR
not the crank sensor
not the rpm sensor

the fuel is really lean up to about 3500rpm. It bucks a little to that point. When the boost hits it hits like a freight train and when the 6th injector fires the fuel mixture gets into the low end of the acceptable A/F mixture readings.

Since the 6th injector fires and brings the fuel up a touch I assume the fuel pump and filter are alright.

Since the 6th injector firing sends a good signal to the A/F meter the O2 sensor should be alright.

The only thing left is the CIS dizzy itself. What should I look for there?

Any other ideas? I'm really stuck.

One thing is for sure. When the fuel is right through the regular boost range this car is going to FLY!

Re: OK.. here is what it is not...
 

check the air plate adjustments.. if its out or binding it will cause that problem. Check the frequency valve on the front of the fuel dist. and the sensors on it.

Are you sure about this.............
 

"Since the 6th injector firing sends a good signal to the A/F meter the O2 sensor should be alright." I am not sure that this is a correct statement. I am hardly an expert, but I don't think that the 6th injector and the O2 sensor work in unison.

A bad O2 sensor causes bad driveability problems. The correct rich/lean mixture gets screwed up. I don't know how to test an 02 sensor for reliability, but if yours is old with a lot of miles, you may want to change it to see if that corrects your problem.

The dizzy doesn't break very often. I have one that is operating properly with about 300K miles on the clock. The dizzy has never given me any trouble.
Regards...............Rooster

Can you temporarily go into or go back to "stock" for troublshooting?

Re: Are you sure about this.............
 

I'm quite sure. The mixture at idle shows the second green led so that is set just a hair above the leanest and safe setting. The car idles wonderfully.

When the throttle is pressed and the engine comes of idle the misture leans out back to the first red LED - VERY lean.

It stays here until the 6th injector fires and then I get up to three green LEDs and the power comes back somewhat.

I think Black-Wolf may be right. If the fuel frequency stuff has gone south and the failed condition is no pulsing, then the fuel making it through is going to be about as lean as can be.

Geez, I hope this isn't too dificult.

Will pulling codes confirm this? I need to fix my check engine light then.

Not really... if you have a bentley there is test procedures for all of them....
 

It sounds more and more like a sticking air plate.. reove the dreaded boot above the air plate and see if the plate moves freely up and down and that it is not hitting the housing. A solid backfire will dislodge the plate and knock it out of adjustment. The 5kcstq we just scrapped had the same problem and we tested it this way. The plate moved hard up but easy down. Replaced it and it ran sweet.

Agreed. Sounds like air plate not responding.

Here is what it IS... I think
 

The fuel system frequency valve is not making it's usual clicking noises. I can see from it's location that this will be a major PITA (nothing new!)

At any rate, this should be it. Any BTDT advice?

Thanks for the tip... I'll check that too.