Hello Robert,
This is what i would do in the sequence specified below. I am assuming that your CEL is NOT on.

1. Check your OVP relay...it is located behind the battery with a red top. Make sure the fuse on top (10a) is OK. Also when you put it back in MAKE SURE IT IS SEATED PROPERLY IN THE SOCKET..a snug fit.

2. Check your cold start valve. Make sure you're getting current to the CSV. If the OVP is bad chances are the CSV is not getting any current and thus your rough idle issues & dying engine.

Please post results.

smk_texas