Howdy all, I'm Bob. I have a 2000 LR Disco II. It has 147,000 miles on it and here is what is going on. Last summer I did the Bosch +4 plugs, 8mm magenocores, and the intake seals while it was apart. Just lately, I started getting some misfire codes. They were on 1 and 3. I pulled the plugs and bother were black. I replaced both and made sure that the wires were seated properly on the plugs and on the coil pack. I cleared the codes, but they come back within 30 miles or so. The codes that it is throwing right now are:
P1300 - manufacturer control
P0301 - misfire cylinder 1
P0303 - misfire cylinder 3
P0300 - random/multiple misfire

I'll be honest and say that I don't know what to trouble shoot next. All I can think to do is replace the coil since I didn't do it last summer with the plugs, wires, o2 sensors, and seals. Please hit me up with any thing else I can try before I try to pull the IM again. Since the mileage is climbing up there, I am going to have the fuel system cleaned today after work if possible.

Bob

 

You replaced the 2 plugs with new one's? You may have a couple of clogged injectors. What grade of fuel are you running?

 

Thats what I did and it worked....

Weird, but, but it took away the rough idle and random misfire codes... after plugs, wires and a new coil pack.. The O2's cleared everything up and i am getting much better gas mileage.

Just my 2 cents,

 

Last summer when I did all this work, the truck ran like a champ, it was great! I have been running high test and sometimes medium test gasoline. The truck definitely has a rough idle at the moment. Specifically when it is in gear. If I leave the truck in park or neutral the idle is not as bad, but still not the prettiest it has ever been.

I have not done the coil pack yet, I am going to try to have the fuel system cleaned and hopefully that will do it. I was wondering if there might be anything else to try before just doing the coil pack. Pulling the IM again just really REALLY does not entice me at the moment, hahaha.

 

Run 91+ all of the time. No exceptions...period.

Clean the fuel system and see if that helps. I would also suggest a can of BG 44K in the fuel tank every other oil change.

 

I wouldn't go throwing 2 new coils at it.
Pull the 2 new plugs and tell us in detail what they look/smell like.

 

I will do that tonight, I have an appt to get the fuel system cleaned and I found a place that carries the bg 44k in town (luckily by my daughters daycare). So hopefully, after the cleaning, I can get the truck to the house and look at the plugs.

 

Actually, I won't be able to pull the plugs tonight, but I got the fuel system cleaned today and I put the bg 44k into the tank. I also reset the codes on the computer, so let's see what happens tomorrow.

 

+2 on hi ocane all the time not some of the time

 

I should re-phrase what i said... after i changed the plugs and wires and coil pack, i still had a rough idle. ONLY after changing out the O2's did the rough idle go away and the gas mileage improve.

Sorry for the confusion.

Thanks,