It was always while I was driving on the freeway. I'm assuming the "3rd speed" on the FPCU was going out. When I slowed down or idled, the problem went away. I thought it was the PTU for the longest time, but then I pulled FPCU and did the bypass. No issues after that. Located a used FPCU to replace my existing unit. Good luck.
-baggar11 1987 300zx n/a (sold) 1990 300zx TT |