What are signs of a bad rotor cap or bad ing.

 

A misfiring engine (sometimes the SES light will blink), a bad miss/stumble below 2,500 rpms are a few.

 

Its weak as hell especially in low rpm's. The SES light has came on and doesn't come back on when restarted. What does that code read.

 

When my cap/rotor went out I had a slight missfire throughout the entire rpm band. Sometime it can be really bad and sometime not even noticeable, mine resembled a bad batch of gas. Turned out that #8 had little to no spark at all Goodluck!

 

When my opti gave up the ghost, it started out as a stumble in the low RPM's, but was still rock solid above around 2 grand. It then progressively broadened throughout the operating range of the engine.

If you put it on a scanner, it'll tell you what code it is, i dont' have it on the top of my head. you can also search for DTC's for your vehicle on the 'net or a book.