Some years ago I got that P0089 code.... It was 122,xxx.
Im now at 151,xxx and It has not happened again.
I only used HEET, in case it was water in fuel. And Techron in case it was carbon.
"on the highway- my CEL flashed for about 3 seconds.. maybe 6 flashes... (not solidly lit). Not even enough time to make a lane change.
I felt a bit of a stumble.
It did not set the CEL.
So far so good at 3500 miles into the trip----then flashing cel... then continued for another 200 miles to complete a 3700 mile trip.
When scanned- it showed P0089 and P0305 pending codes
52 misfires were shown on cyl 5.
1 day later and P0089 is gone.
no more misfires either.
Ill keep my eye on it.
But could be carbon buildup--- as I now have 122,xxx.
or- an issue with the injector on #5. (based on another thread on here from a member who got P0089 and P0305 and some other codes--were an injector change corrected the problem).
MPGs on the trip were excellent- and just that 3 sec blip...."