So first off, it's an '87 Camaro IROC-Z, with the 305 carbed motor and an auto. Everything's stock, no mods.

A few months ago, in November I think, something went wrong with the speedometer cable, once I hit a speed around, 25-30 mph it would make a horrible whining grinding sound, but it only did it in cold weather.
Then about a week after it was happening, my dad unhooked the speedometer cable from the top part near the gauge, under the hood.
Then my mom drove it out of town and it completely died.
My dad replaced the ignition module, distributor cap and ignition coil, because they were no longer working.
I posted about the speedometer cable and someone replied that it would make things worse, because the computer would be missing information from the speedometer.
It's been broken down since then and now it won't throw trouble codes when A and B are jumpered, and it runs rough like it isn't timed for a few minutes and it eventually smooths out some.
I need to know, would that have damaged my ECM? I really don't have 90 bucks for a new one, and don't know of any junkyards near by.
Any help would be greatly appreciated, and thanks in advance!

 

NO.


If the ECM operated the Check Engine light operate as it should ( with and without the ECM in diagnostic mode ) Than the ECM should be fine.

 

Now the light stays lit still, but turns over like halfway once when I try to start it.