Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
zeros on the trim is actualy good. Have you checked for any codes being set?
What cylinders are miss firing? Are you saying the trim does not ever change?
How old is the cap and rotor button?
What brand did you use?
Can you pull the cap off and check the rotor button and see how far up you can pull it? Also check the metal tab on the tip and see if it looks like it has been hitting some thing?
If the trim is staying right around 0, then it will not be due to air flow or a vacuum leak. That only leaves timing or compression.