I think I may know when your problem occurred. I ask because in your first post it states you have recently changed the fuel filter. I’ve been taught to always change my fuel filter right before a tune. For the fuel filter accumulates particles and what not and begins to get clogged after monthly/yearly use. A lot of peeps aren’t aware of it or just try to cut corners and tune on a fuel filter that has been on the car for years!!
So when one tunes with a used fuel filter it causes slight to significant restrictions in fuel delivery. So what a tuner will usually do is increase fuel or fuel pressure!
Now, let’s say this is your scenario. What happens once you’re tuned and you decide months later that it’s time to change the fuel filter............ WELL, it’s going to cause you to run rich for there is no longer a restriction, meaning a re-tune is necessary.
May this be the cause? Any questions?
