I have a 86 Z28 305 TPI and i get 43 code, i replaced the rotor cap and coil and the car still doesent seem to know when to fire. runs ok for about 5 min then the Tack bounces all over and car dies....i'm out of ideas, anyone know???

Well to me it sounds like a ignition module issue because if im not mistaken it also drives the tach and they can be sensitive to heat but the code 43 would be something to explore first. A code 43 is set when the ECM sees a constant knock condition even after pulling back the timing. The output of the ESC module send out i believe 8-10 volts back to the ECM to let it know everythings ok and when theres a knock it drops to 0. I would start by seeing if the ESC module is putting out the everythings ok signal. If it is then theres a broken wire or bad connection to the ecm if its not putting out that signal it could be the ESC module or anything befor it.

ok i found that the module is good the prob was there was a bolt grounding the pickup coil to the bottom of the distributer, fixed that now i still have the 43 code along with slight engine deatonation....timing is @11* BTC manual sayz it sould be @6 or 8 but runs like crap that way,....stuck again

Well the reason probably is because the code 43 means the ECM is detecting a constant knock condition meaning the ECM is constantly retarding the timing. So advancing the base timing like you have done in a sence negates its effect. Now it wont run good like that because the ECM can only control the timing correctly when it knows what the base timing is. In this case again the ECM thinks its set to 7 degrees or so when in reality its 11 degrees so the timing will never be correct. Again the first thing I would do is measure the output of the ESC module to the ECM.

sounds like you are on the rite track, but i'm looking at the electrical schematics and its showing the ESCM is not even linked to the distributer just to the knock sensor and the ECM. is thie ESCM different from the ignition caontrol module in the distributer? anyway ordered a new knock sensor shoiuld b here in a few.

Well it is a different module than the ignition module and its not directly connected to the distributor but the ECM controls the timing and one of the things the ECM uses to decide the appropriate timing is the ESC modules output. So even though its not directly connected it is connected in a round about way.