Low spark on one spark plug

USA spec car no not? no country of VIN told so answers can be big time wrong, ok?
sure get a shop to fix it
they have tools you don;'t have.
3.0L is inline 6? called L6
is this car with coil pack that does more than one spark wire?
or have 6, COP spark coils, (all I can do is guess)
or USA has 6 COPS
we check compression first, x6.
got cam timing chain NOISE?
I guess changed word mean replaced, with new COP coil?
well; engine is first , the spark then fuel injector
do DTC P0301 was set, and is still set this error, be specific on DTC errors, even tell them.
301 means weak combustion on #1

• bad cylinder compression
• bad spark
• or #1 injector is bad.

why 3 and 5 fails and all are odd cylinders./
is odd but I suspect VVT problems./
no mileage on the engine told. 300k 400k?

The 3000 mule I have worked on has a coil, wire which screws into the coil and spark plug boot.
Do you have power and ground connection at coil.
You said you replaced coil did the wire and spark plug boot get replaced also.
If there is any question about the connection between the coil, wire and boot you might try removing the coil, wire and boot from back cylinder and placing on front. Swap them and see if you loose spark on rear plug after swapping.
Just a thought.

Cause of no spark can be determined by process of elimination. Good to have a new sparkplug on hand to eliminate plug as fault. So start by replacing plug with new or test plug on mower /edger etc. for spark. If plug ok, then temporarily remove the wire connected to oil alert system (oil alert will ground coil if oil low or dirty). With oil alert unpluged, and no spark suspect sparkplug boot or coil. The sparkplug boot threads on to the spartplug wire and is what actually fits-on to the spark plug. You can test the coil by removing the boot and inserting piece of paperclip wire, or small screw into end of the coil wire and hold close to engine ground while pulling rope. If still no spark suspect coil. If spark, replace the boot. Good luck with repair.

Please make sure that the trigger required for the coil to give out the High voltage to spark comes from the pulsating voltage at the coil LT( low tension).
So check for the make /break on the coil- on one side you will need the positive and on the other the trigger. Once this is seen then the distribution can be checked, check the HT wires and contacts in the distributor.

No spark.This is indication of faulty spark plugs.But spark plugs get power to spark from coil pack. So get the connection between coil pack to spark plugs checked.If it checked out ok then its faulty spark plugs that has to be replaced,but if coil pack has no power then its faulty coil pack that has to be replaced.But if coil pack and spark plugs both checked out ok then this problem is fuel related problem.In this case the fuel pressure needs to be checked.The fuel pressure can be easily checked at any local car garage.If its low then its faulty fuel pump as well as clogged fuel filter,which has to be replaced. The voltage for spark plugs and coil pack in voltmeter will show 12 volts.Its a 12 volt part.If there is no or low volt then there is problem with the part. ------------------ Keep updated with any more queries.Thanks.

Bad MAF sensor.

take the spark plugs ou but the xj 600 has 2 coils so take the corrasponding plugs out two at a time for each coil put one plug at a time on the engine block turn the engine over look for a spark between the electrodes when turning the engine over and if you cant see a spark buy a new sett of plugs and if you still dont see a spark follow th HT lead to the coil and replace that coil with a new or a working coil be carefull tho you dont want a shock of a plug or a coil its about 50,000 volts at low ampage it will hurt or could kill you if unsure ask a qualified mechanic.

You still need to check the spark plugs. In the ignition system the coil is the least likely problem. I would rank the likelyhood of problems: 1. Spark Plugs, 2. Wires, 3. Distributor cap (if you have one), 4. Coil, 5. Low ignition voltage. Good luck, be sure to cover all bases before giving up.

check and see if you have spark at the coil you can do this by getting an inline spark tester no more then ten dollars if you have spark then try replacing the distributor

sounds like coil pack, when your coils break down due to age the spark then jumps from the side of the coil to the alloy head, i would recomend taking the coils out and getting them tested to be 100%.