Bertie_A

I have a 98 4.0L sport with has had a rough idle for a while, so changed out spark plugs, ignition coil pack, and crank position sensor and it solved issue for a while.
Then got a misfire code on cylinder 1, not sure if it was a bad plug and not having a spare on me, switched it with plug 2 to see if it happened again would it be 2 but now getting misfires on 3, 4, and 5 with the flashing CEL having appeared twice. Have coolant leaking somewhere, not making it to the ground though.
Temp gauge has never gone above normal, driving fine apart from rough idle and CEL staring me in the face!
So head gasket or cracked head?

ps also had a power gauge spike while driving recently, never cut out but it would not restart for 5 mins, replaced the battery and cleaned the connections and that problem hasn't happened since.

fishbone

Besides the guage spikes, these are all classic symptoms of a blown head gasket. You're gonna have to dig a little deeper before you make that diagnosis. Id start by running compression tests on the cylinders then check for a presence of coolant mixing with the oil.

dave1123

You'll have to do a search, but there is a test for a blown head gasket involving a device that fits on the radiator cap with fluid in it and the fluid will change color if it detects combustion gases. It's quite simple to test and ensures the gasket is blown or not.