Hello first time poster here. Here is my situation:

- 2003 Land Rover Discovery II S

- Replaced plugs and wires approx 15 months ago (15k miles). I attribute that episode to lending thevehicle to my wife employer (I didnt warn him, my fault) who filled the tank when he was done, but with mid-grade.

-Recently (month ago) lent vehicle to my Step-Father who filled to half tank with mid-grade (I didnt warn him, my fault, last time that will happen). Last night on way home from work check engine light came on, stopped and purchased Lucas Fuel treatment and put in today after work with quarter tank in it then capped off with premium. Stopped and had codes done and it showed P0300, P0302, P0303, and P1300.

- My plan is to wait until the Lucas Fuel treatment has run its course, then switch out the plugs (would like to avoid removing plenum to get at the coil pack to switch out wires) and use the Lucas Fuel treatment again? My concern is that I will damage the Cat before the Lucas does its stuff, but I dont want to put plugs in now to get fouled with the treatment breaking up all the stuff thats in there. In more detail I plan to burn through this tank of gas (down to quarter tank) and then switch out plugs and live out the rest of my life in maintenance free Nirvana? Any constructive suggestions or cautions from anyone is welcomed.

Thanks in Advance!

 

I doubt a tank or two of mid-grade will affect anything in the short-term. What plugs and wires did you use and how many miles do you have? I think those are cylinder2 and3 misfire codes plus random misfire. You could pull those plugs out and take a look easilly enough, but it could just as easilly be bad wires too. Make sure you check that all of the wires are locked tightly at the spark plugs and at the coil. Cylinder2 and3 might ground through each other, i really don't know. If so, the wires might be bad - take a very close look at them.

 

For get the Lucas, it is not made for that application.
Do you have any fault codes?
What brand of plugs and wires did you install?

 

Mleage is at 60,000

The plugs were Bosch that I installed last time.

The wires I am unsure of the brand, I purchased them through a local shop that specialized in Land Rover and "English" cars.

In both cases the people involved could have easily used low grade gas and told me it was mid-grade.Ifit isnt the bad gas what else could it be. Just odd how both incidents were roughly 1 month after a bad tank.I automatically assumed the gas, what other underlying problems could cause the CEL and those codes? Certainly changing the plugs &wires once a year is a bit excessive...?

 

It is not the gas.
I would like to have you go see what brand of plug wires you are using, should be written on the side of the wires.
Are there no check engine lights on?

 

Codes were:

P0300
P0302
P0303
P1300

Although today the engine starting running well again (still has a couple chugs in it, but 99% better), then when I went to lunch the Check engine light went off. Still going to check the plugs, but looks like I am out of the woods with just using the fuel treatment. I am thouroughly convinced about the gas problem at this point, although I am certainly willing to entertain other ideas. The wires I replaced just 15k miles ago, I will get back after I change the plugs Saturday morning with the brand on the wires and my findings on the plugs.

 

In the end, do you know what the solution was?

Thanks!

 

this thread is almost 9 years old man. Are you having these issues?

 

Ha! But yeah I am getting P0300, P0302, and P0303 right now. I replaced the plugs, also have a valve cover tick at the moment.

I bought new coils, and planning on replacing them with my valve cover gasket job soon.

 

what plugs did you use. I went cheap and it threw me codes like crazy