Engine runs great going to work 50 miles on interstate. Out of no where the engine just starts stumbling and misfiring and has hardly any power at all. Make it half a mile and just as fast as it fell on it's face all of a sudden all the power came back and everything was good again. Left work and made it half way home before power just dropped out and engine started misfiring again.

I cleared the codes while driving a couple times. I'm getting two main codes that relate to the symptoms.

I'm getting
P0305 (misfire on #5)
P0300 (random misfire)

I had a coolant temp insufficient for stable operation code... umm.. and a couple O2 sensor circuit codes.

Just so everyone knows I installed new coil packs, new plugs, 10k mile old plug wires and did a compression test on #5 and got 120ish on a cold engine with a closed throttle body. (I don't think compression is an issue.. plus I'm getting *random* misfires)

i have put in new spark plugs,coils,catalytic converter. Over $3000 but still same problem. Can someone help me pls.
thanks.

 

What Land Rover do you have