Replace the air filter with a standard paper one, reset the code.
Cheap plug wires will not last, neither will a non OEM cap and rotor.
Spark plugs make no difference as long as you bought the correct heat range.
Weak spark/mis fires will set off O2 codes, universal O2's will set off O2 codes.

 

it doesn't have a cap and rotor. it has the four coil packs in the back of the engine bay. i did buy the lifetime warranty 7mm wire. really not to fond of them but seem to work. i will try doing another tune up and see what happens.

 

Sorry, I forgot that you had a '99.
I bought Duralast wires from AutoZone when I first got my truck not knowing any better.
First set lasted a year, lifetime warranty, second set lasted a month, 3rd set lasted 2 weeks.
Kingsbourne plug wires are a great set for not much money.
You can return the life time warranty ones from the local parts store for a full refund.
I have Magnecore plug wires, 8mm.
7mm is the OEM size.

 

wow sounds horrible. guess its time to head back down the hill to the parts store and see what i can do to get new plugs filter oil and filter then pull all plugs out and clean them up. if my wires are causing all of this then im sure my plugs have seen better days. hope after this the codes don't come back. but still can't complain for paying 1700 bucks for the truck.

 

The problem with spark plugs these days is they cant be cleaned, one time use kinda deal.
Just buy $.99 copper plugs, stay away from Autolites, they are pure junk.
Champion copper plugs are what came in it from the factory.

For $1700, you cant complain that you have to put $500 into it.

 

Man I just put the autolites in it. Wtf I have done it all wrong from the start. Thanks for the good info.

 

I had a really really rough idle at one point that I had to diagnois, bought a set of Autolites from Wal-Mart for like $9.
Rough idle went away, plugs only lasted 6 months before I had random mis-fire codes.
Switched to Autolite Iridium's because the Denso's were on backorder and I didnt want to wait.
Those plugs only lasted 1 year.
Now I have NGK plugs, I forget which ones, but they were $2.50 each.

 

im going to be pulling the plugs out tomorrow or Thursday to see what they look like. i will also be dropping the oil as well. then clear the codes once i put new wires on AGAIN. and i will hope that the codes stay away. i think soon as i clear the codes im going to drive it to another town and back to warm her up and then smog her.

 

So I got off the phone with a few of my mechanic budies and they all said the same thing. Autolites are crap for any import. They work great on old domestics but when it comes to land rover stick to factory. Which is what you said copper plugs. They recommended ngk's again what you said. So that makes it pretty clear to me I put in all the wrong things. As for my wires I will keep unless the rough idle keeps up.

 

Sounds like a plan.
Keep us posted.