Can a bad ESC module cause a bad idle?

While checking my base timing, I noticed with the wire unhooked (the brown one you unplug to set your base timing), the engine idled smooth. No shakes, nothing.

When I hooked it back up, my rough idle came back.

Is this a sign of a bad ESC?

History:

I have been experiencing a progressivily worst idle over the last months. Checked the usual. Replaced the IAC (original equipment!), replaced TPI gaskets, checked obvious.

Last week, I decided to try a backup ECM and a 1 year newer prom. I wanted to see if my backup ECM was good, and what the heck, a one year newer PROM might have some fixes in it (1987 vs 1988). During a WOT test, the engine pinged! It never did this with the other prom. So I was thinking the 1988 PROM might be agressive in the spark, but the ECM should retard the timing when a knock is detected, right?

So perhaps some more input towards the ESC module being/going bad.



Is the ESC module the same with TPI, TBI, V8 - V6? I have one from a 1989 TBI. It that would work, might be a good test.

Thanks.
Mark.
1985 Jimmy. 5.7L TPI. Edelbrock RPM Heads, ZZ3 cam, 52 mm, AFPR, ported upper/lower, etc. etc. etc.

One situation After switching to a newer PROM, I noticed the engine would ping at WOT.

 

I went through the same thing after I bought my car. It would idle fine with the wire unplugged but after setting initial timing and plugging back in it would miss at idle and ping at wot.I replaced the knock sensor and it quit pinging, I replaced the plugs, wires, cap, rotor, pick up coil, ignition module, ignition coil and tried a new ESC module and still could not get it to idle smooth with 6 degrees initial timing and what ever more timing the computer gave it ( with wire hooked up). After too much money and high blood pressure I backed it off with the wire hooked up without the timing light and it smoothed out completely and ran better. I guess the outer ring of the balancer may have slipped some or the timing tab is in the wrong location so I just made a new mark where it started idling smooth and adjusted from there. I'd try setting it by ear and see what happens.