I just went thru the same thing with an MSD opti. It took almost 2 weeks to manifest but the problems sound similiar. After install it worked great for 2 weeks. Then all the sudden once car reached operating temp the check engine light would come on and it seemed like the motor was being held back. Once you shut the engine off it would be difficult to start until it cooled completly down. The it would start and run fine until the engine warmed up then start all over. I replaced everything ignition related, plugs/wire/module/coil with no resolve until i replaced the MSD opti with a GM one, instantly problem fixed. Yea it sucked and the time and labor expensive. 2 optis in less then a month. Hopefully you will solve without going through the same problem but im not so sure of MSD quality or maybe I just ended up with a bad one. Good luck and maybe this will help you out a little.

 

This is the fifth or sixth complaint I have read about the MSD opti. AsI had previously mentioned, the design is probably good, but they haven't taken care of the bugs before putting it on the market. That is just my opinion.

 

ok thanks... i hope its not his opti, but there is a 1 year warantee, itll just be a pain to do.

 

ok would if it dosent give you a code. i think my pcm is out becouse it blinks 12 over and over whitch isnt any thing. and i have replaced the opti. but i cant get a coad there isnt any thing it runs but missfires. i have no clue i just got a pcm on its way there are only 3 that are in the usa in the dealers. idk i hope that is the problem. eather that or i think it is the icm i should have changed that first is there any way to test that