Una parola sulla ECM : non erano il massimo, a volte fanno brutte sorprese
rough idle problem... solved

After checking the wiring adnauseam, cleaning and reinstalling grounds, the code 43, knock sensor circuit, continued to recur. I replaced the ECM, reinstalling the original PROM in the remanufactured ECM. I am approaching 100 miles without a problem. Previous to the ECM change, problem would crop up immediately or after up to as many as eight miles.

What I have learned through all this is that there are many things that can go bad and result in the same symptoms. Thanks for all the input. I ended up spending about $200 on parts and quite a bit of time learning some basics.

I will repost if the problem ever returns. Now, on to that persistent seat belt reminder light.