So I'm getting the SES light and codes P0300 and P0306. Did a search here and looks like a misfire on #6. I cleared code twice with ultra gauge and it came back.

Recently did the Seafoam induction cleaning, could that have caused this?

I have, in the past 1 year, gotten new head gaskets and while they were being fixed (I brought to a LR indy shop) they also replaced wires and plugs.

Any suggestions as to what I could check? Saw in another post to get a compression test, if I have to go that route I figure I'll just bring it back to shop that did the head work.

Thanks.

 

I had a similar issue pop up with those exact codes. My problem was my coils. That being said, there are bunches of things you need to eliminate before you go down that path. Check the plugs, check the wires to the plug and coils. Run the engine when it is completely dark to see if you see any sparking, you may have a damaged spark plug wire.

 

Thanks, any words of advice for how to check? I am grabbing Rave now to read and I'll search here too but I don't want to hose anything worse or zap myself, etc.

 

Forget the coils, I bet at 90,000 miles you are still running the old warn out factory plugs and grey plug wires, time for a tune up.
Also clearing the code before you fix the problem is a waste of time cause yes, it will come right back.
Have you had your major service done yet? Might want to read mine posted at the top of this section and pay attention to your drive shaft, if it has not been rebuilt or replaced, your are living on borowed time.

 

In the absolute dark, run the engine and watch for small "bursts" of light near the plugs or at the back of the intake manifold. If you see any, shut off car and make sure that the spark plug wire boots are firmly in place. If #6 was loose at either end you may have located your issue. This is one one of many possibilities. My coils had to be replaced at 86k.

 

Thanks Mike. I've done all the major service things except the brakes.

I had heads done 1 year ago and new plugs and magnecor wires installed - I hired a shop for that work, I'm still learning and was a "rookie" last year.

The only reason I cleared the code was because I just did the seafoam last week and figured it might be related.

FYI, I also put on a replaced air intake hose, I had snapped that IACV portion so I got a used one from Paul Grant and it was easy to install. Only mentioning in case it might be related.

As for the driveshaft I've got a TW one and I greased it all - including that infernal centering ball - last week as well. I'm running 15w-40 rotella too. I do my best to listen to the advice around here!

Thanks.

 

Check the rubber boots which go over the sparkplug.

See these little boots?
NAPA auto.
Those are the ticket for your NEW wires!

 

So you are saying I get those booties to fix problem? Not sure I understand, do they just go over existing plug wires, are you tooling on me, etc?

This is the first vehicle I've worked on so please excuse stupid questions i may have. I have done fluid changes, driveshaft greasing, transfer case reseal, etc. I found diagram here showing plug wire numbers and routing. I stuck my hand on spark plugs in my truck and 6 didn't seem loose but I am nervous about braking stuff or getting zapped.

Trying my best to learn as I find it incredibly rewarding but if I mess up too bad the wife will put her foot down and I'll be in a lr3, which might be nice but I'm in love with discos

 

FYI it was the coils, thanks for the ideas. i wonder what is next?

 

I wish I could say that you are good to go for a long time, but we ALL KNOW that is not necessarily true with rovers. Glad I could help.