I had a Lumenition system on the 7, which took about 4 years to die.
I would get a slight hesitancy in acceleration from low revs for the first 4 or 5 kilometres from cold, after which it would clean up. Each time this appeared I would clean everything in the ignition & fuel systems, & the problem would disappear for 6 or 12 months, only to reappear.
It was never testable by the time I got to the auto electrician in town, 26 kilometres away. At it's last appearance it got bad enough to actually cut the engine for a second or so, long enough to drop the rev counter to near zero, pinpointing the problem.
I finally found a mobile sparky who came & tested it cold, declared it was the Lumenition module, supplied & fitted a new system. That was about 6 years ago. No further problem, & I think a little more power.