Hello. This is my first time here. So ill get to the point. My 1990 Camaro RS convert. It has a rebuilt 305 with a mild cam (410/420 lift) edelbrock headers and flat top pistons. The engine is throwing a code 43. I know this means an ESC module malfunction. Now i could just keep throwing parts at it till the cows come home but i thought i would try and get some help. I've checked all the wiring and it looks okay. I did change the ESC module. That didn't work. Im running out of ideas and patience. Thanks for the help

Does it run ok otherwise?

I cannot help but notice you mentioned the engine rebuild. When did the problems start? Was it before or after the rebuild? Did anything else change immediately prior to the engine code?

I ask all the questions because many times if you look back you can see what happen to cause the problem.

Well it started just after the engine rebuild. Thats the only problem. Well. Not the only problem. The oil pressure gauge is a little skittish. So im not totally sure.

Yea and it runs fine otherwise.

Check all wiring especially the grounds. The mention of the oil gauge tips me off to think you may have ground issue. All grounds are very important in electronics, because all of the signals from the sensors or relative to ground.
Also check and insure that you connected all of the wiring when you reinstalled the engine.
Did you remove the battery before you removed the engine? Did you let it arch? That also could have caused damage.