Originally Posted by 2000GTP

One of the advantages of the MSD is if you buy the one for your application, you get the benefit of being able to convert to a vented opti by runnning the appropriate vacuum lines. Other then that, there is no real advantage. Converting from a non vented to vented application with a Delco opti is a more involved process.

Originally Posted by REDLT4

Thanks you for the expalnation, but I was wondering how you know the high res pulse count the PCM watches after it loses the low res. I maybe just missed it in my manual, and I'll have to confirm that after I get home, but I don't remember it telling me this under DTC 1371. This info does cause me to question the diagnosis I've made, but do you have any suggestions about what circuit I could setup to watch while driving, and when the malfunction happens, confirm where my problem lies. I'm quite sure it's the ignition I'm losing, based on the fuel pressure test. Could I watch the power to the coil or ignition module?