Dec 10, 2014 - 04:17 PM
To determine if the issue is fuel or ignition related, use a scan tool to view PIDs and fuel trims and see if the computer is trying to add/subtract alot of fuel in order to maintain stoic. This usually gives you a good indication as to if it is a fuel or ignition issue, along with which bank is actually causing the issue. From there you can current ramp the ignition or fuel circuit to determine where the issue is coming from.
If this does not answer your question send more details and I'll work up a better answer.