88 f150 4.9 straight 6 stalling when engine warm
I start the truck runs okay then when it gets warmed up the rpms start bouncing around give it gas to try to save it and it ends up sputtering out. fuel pumps are engaging already drained tank completely and filled with brand new gas and used STP fuel cleaner, PCV is not clogged, cant find any cracks in Vacuum lines, getting good pressure from tail pipe. sometimes it will be fine put it in gear to take off and it will sputter out have to do it quite a few times just to get it back into garage. I am completely stumped.



