Following up on Sugar Bear's suggestions, I pulled one coil, connector, plug and wire and all looked like new. They are all Bosch oem parts that were installed in 2018. Car may have 15,000 miles since then.

At that that time I was having a similar problem with low idle feeling like it was dropping random cylinders and smelling very rich. That is when I installed the new ignition parts and brake lite switch which cured the problem for a couple of years.

In the last few weeks the stumble has gotten worse to the point it doesn't want to accelerate off idle anymore. It will pick up speed gradually and then take off like nothings wrong. It pulls hard and doesn't feel like an ignition problem.

I cut back some of the insulation in the throttle body harness in a couple of places and it looks OK to me.

I bought two OVPs, a slighty used looking OEM and a new Chinese knock off. I'm tempted to switch them just to see.

After I cleared the codes it now just shows #6 using the built in button and #1 on pin #8
There is no CE light

The date code on my throttle body is "94MO8"which I assume is August 1994

Pelican Parts shows a reman throttle body with the correct part number for $920. I don't mind spending the money if it cures the problem.

They also show a Idle air control valve which is Code #6, but I can't find it on my car and assume it's incorporated in the throttle body?

Maybe totally unrelated, but if my gas tank is low and I release the cap there is quite a suction of air. Is there possibly a vent hose plugged some ware?

Thanks again!