I just got a 740 gle and to the extra cost of 400 dollars I have replaced the distributor, the coil , the control unit,cap,wires and plugs...still no spark!!! why oh why? This is starting to get on my nerves!I ve been wrenching for 20 years and this one really puzzles me!any suggestions?

 

Check the engine speed sensor and the power stage.
The engine speed sensor is at the back of the engine on the top by the top of the trans.
The power stage is on the inside of the left front fender.It is a black sensor mounted on a peice of aluminum.