Took my 2001 Land Rover Discovery II to have the oil andspark plug change two weeks ago and now I receiving error codes P1300, P0301,P0306. P0300 with a small backfire. I replacethe mass airflow sensor and check for sparks on plug one and six. Both were good, but I replace bothagain. Reset the error light and ran itfor 5 miles and P0301 came back and began to back fire. Recheck the plug wire for one and reset itand clear codes. Ran again for around 5miles or so and the check engine light came back on. This time I got codes P1300, P0301, P0306 andP0300. What should I do now; I have replacedthe gas and added Lucas octane booster and Sea Foam treatment. If I let the vehicle set and reset the clearthe codes it will run good for 5 to 6 miles before getting the codes back. I pay $2,200 for the Rover and it looks brandnew, I just do not want to place too much money into it.

 

Plug wires are a likely candidate, you want 8mm silicone wires. You may even look under hood at idle in total darkness and see small arcs.

 

Should I try to change the wires myself, I got a set fromO’Reilly Auto Parts, Import Direct 40974. It does not say if they an 8mm silicone wires or not. I did check and did not see any arcs tonightand I put a tester on both spark plugs and got a good arc on each. The Land Rover dealer says it would take 5hours to remove and replace the wires and be around $700.00.

 

The dealer plans on removing part of the upper intake to access the wiring, that runs labor up. Many on here DIY. There is very little space, but the pix below shows plenty of space, if the firewall and rest of the truck are sawed off and slid to one side....

See https://landroverforums.com/forum/di...light=removing

 

In the future, ask for help before you go wasting your time and money. That new MAF was not needed per the fault codes and you bought some cheap plugs from a local parts store that won't ho;d up long.
To answer your question, yes, if you are a little mechanical you should change the wires yourself and save $250 to $300 in labor from a shop.
As Buzz mentioned, you will need 8 mm silicone wires, like STI or Magnecor's that will give you the full 55,000 volts, long life and can hold up to the high heat in your engine compartment. Might want to check British Parts of Utah, they handle both of them.
If you want help, I would be glad to give you some help on installing the wires, send me your number and I would be glad to help with this.
Might also look at the sticky posted at the top of this section on Major services needed. It would be great if you did this yourself, you will save hundreds of dollars, $500 or more, and you will learn what makes your truck tick.

 

I will try to do the job on Monday to see if I can fixit. Thanks

 

The stutter...wires are 7mm...no way? Frikken idiot used car dealer. Lovely clean and wax job on engine. Would have been better to spend on 8mm as all info mandates. Does 98 Discovery LE have wireless key compnent(s)?