My 04 Disco II runs rough when it is first started after sitting in the rain. Get general misfire codes. 168,000 miles- replaced plenum gasket 3X, wires and plugs 2X. Considering replacing the coil packs and running 8mm wires with +4 Bosch plugs. Strange that after it warms up it runs fine- hairline cracks in the coil pack allowing moisture in? Should I replace the intake bolts when doing the gasket- do they stretch like headbolts? Will be 4th time for plenum- noticed antifreeze dripping down the back again.

 

You might have bad head gaskets and the coolant is making the engine run rough at first. Post the exact codes that you have and also mention if you have any warning lights on in the dash.

 

If I had bad head gaskets wouldn't the misfire happen all the time- not just when its wet? Wouldn't I also see antifreeze mixed with the oil? The codes were specific cylinder misfires- 1, 4, 5, 8. The vehicle starts fine when its dry- cold climate or warm- only when it rains it misfires. I have a solid check engine light and the Amigos visit at times. Dealer was unable to clear the solid check engine light.

 

I forgot about you mentioning that it only happens when it rains. Again, post your exact codes (p1050,p1344) and also tell us what grade of gasoline you are using. It could be a bad ground, your mass airflow sensor or oxygen sensors. It could be the coil packs but they rarely go out at the same time eventhough your truck has 168,000 miles. I would have said wires and plugs but you have already changed them more than once.

 

Doesn't seem like you issue, but FYI: no, you won't always have mixing in either/both directions with a bad head gasket, and you very well could be leaking so little coolant into a cylinder that you may not notice it in the exhaust when running. When it will first present itself is on startup (running rough) usually the next morning....because if you run it to temperature and **** it down, the pressure in the cooling system can still keep pushing coolant into the cylinder(s). You get the rough running as it burns this off on the next start up. Until it gets worse. And it always will.

 

Who's wires are you using? If the coil is cracked, better be shopping for a new one, especially at your mileage.

 

Wires are stock as well as plugs. Don't know if coil pack is damaged- just trying to figure out why this only happens when it rains. Rained all night and here are the codes:
1. P0300- Random/multiple misfires.
2. P0301- Cylinder 1 misfire.
3. P0305- Cylinder 5 misfire.
4. P0306- Cylinder 6 misfire.
5. P0308- Cylinder 8 misfire.
6. P0306- Cylinder 6 misfire.
7. P0420- Cat
8. P0430- Cat
9. P1300- Multiple misfires.
10. P1319- Misfire with low fuel level.
11/12- P1412 and P1415- Don't know what these are.

Is it common for the plenum gasket to be replaced so frequently? The dealer has done it 3X now and I won't go back there (not enough space for that one). Magnacore, Kingsborne, or STI 8mm? Looks like I'm doing CAT's too- Magnacore or Borla? Any cheaper options? I assume I can't just cut them out- it would undoubtably effect the delicate balance that is so typically Landrover. I would really like to figure this misfire issue before I put on the new CATs. THANKS FOR THE HELP!

 

if your coil pack is craked, this works w bad plug wires, let her run in the dark and you can see the electric arc, or if you dont mind being zaped fingure along the coil and wires until yo get zaped.Dont wast your money w larger wires, you will loose power, unless you get MSD ignition box, and coils. Check your spark plugs to see if they are wet, if wet smell them, if it fuel it will be a bad plug, wire, or coil, yes check them all, if it smells like coolent then your head gasket is bad, or your heads are warped.Best thing to do, is go to a parts store rent there O.B.D 2 scanner get the codes of it, and then clear all your codes and see if the same codes show up again, as some of these codes could be old and where never erased completly in the computer.Good Luck!