Welder7018

Joy... its just a cylinder 8 missfire... now to compression test it. Whats the range for good compression on the 4.6l... and yes all maintenance is up to date on it.

Carcrazygts2

Depends on the mileage. I have seen well maintain 200k mile 4.6's/5.4 make 165-180psi in each chamber. I have also seen 60k beat on 4.6's/5.4's only make 60psi. In these engine anything less than 125 can cause a low speed miss.

Welder7018

Thats whats going on with my truck. Its randomly missfiring on #8 under 50mph. Im wondering if its possible that having cooked heads and blown headgasket cause this? I know my driverside head has valve seals eat up.