Does anyone know what can happen to a stock ECU, if while the car is running, the +ve terminal on the battey is grounded off to the body for a couple seconds, what can be the possible problems faced....
Also, where would I be able to pick up a good stock ECU
for a JC Cosmo w/13B-REW .

 

By grounding a positive voltage for more than just a split second, you may have run too much current through any number of those little transistors and diodes in the ECU. I would be willing to bet that if you are finding problems after you did this, then this is the cause. It is very bad to short the +Ve to ground, and you probably need a new one. As for finding one, just do a search in the For Sale/Wanted section with your ECU number and you'll probably find a few leads.