An engine code will appear if a sensor, fails breaks etc. Other check engine lights will usually appear if something is definitely wrong, Such as when my crank bolt broke and it lost vacuum, manifold pressure, etc. It might not come on if the problem is intermittent. I know from experience that as long as the computer knows it is getting spark it will provide fuel. As soon as it knows that it is not getting spark it will cut the fuel off. In my case it was getting spark as far as the computer was concerned but as far as the engine was concerned it wasnÆt getting enough. The engine code will be out put from the computer in the form of an analog signal, i.e. a sinusoidal wave function (a series of long and short pulses). The function can be determined using an ANALOG volt meter or an O scope. Digital meters cannot read the signal fast enough to process. Hope this helped you out. Anybody feel free to correct me if I am mistaken.

And to me your problem sounds like a fuel related problem, intermittent pump maybe or bad injector. Too much fuel or too little. If you get spark itÆs probably related to a fuel issue. I had a similar problem where I had two bad injectors that were stuck open. When it sat for a while they drained the fuel from the rail. It would take a couple of seconds to build up pressure before it would fire. Good Luck!