hate to say it but if you are getting the random code #36 the problem might geta little worse.i second craby's opinion.when i started randomly getting that code i had hoped for something else also.changed plugs,wires,ect sensor,tps,coil,icm.et.but it all came back to the opti.see the post"a couple questions".

 

lsxtune.com has the opti harness for even less

 

I just felt a bucking jolt from the engine while driving and the check engine light came on when I got home and turned car off it would not start right away and started only while holding ignition in the start position while starter rotated the flywheel many times over. Hooked up my scan tool and also got this dtc 36. Just bought this car about 2 months ago but can't complain, this is actually my second LT1 Z28.

 

180k miles on the opti? Not bad. Don't worry though, replacing the opti isn't all that bad. Trust me, I just did it, so I know. Haha. Just a lot of stuff needs to be taken out to reach it. Wouldn't be a bad time to flush the radiator out if the coolant is looking ugly. Let us know if replacing both the connector and opti clear the code.