I have a 2000 Dodge ram 5.9 magnum with 158,*** miles on it. I have been loosing oil for a wile now and been trying to figure out where it's going, I have changed the plenum, intake, and valve cover gaskets on it but I can't seem to figure out where I'm loosing about a quart or oil a day. It doesn't smoke or leave puddles in the driveway also I don't see any oil on the engine, it all looks clean well as clean as an engine​ can be really. Anyway I took out my spark plugs one by one and checked them for oil on the to see if it was burning the oil well all of them where clean, and by the way I as I was going through them I put the plug wire back on each of the as I went now I'm getting the falt codes for a missfire in cylinders 6 and 8 and a random missfire code as well. I have went through everything I could think of and various other things I found online (checked resistance in plug wires, checked if all plug wires where connected and to the right spots, checked resistance in the injectors) and everything seems fine but the problem is still there. Any help would be greatly appreciated. Thanks

 

Welcome to DF.

Time to do a compression test. 6 and 8 are next to each other...... may have a blown head gasket.

 

I had opened a thread over 2nd gen vans not long ago having the same misfire codes as you, 6 and 8 and random misfire. I haven't done my plenum yet but have the hughes kit ready for when I do it, I lose about a qt. per one thousand or so miles. Mind you I'm no mechanic, just interested in working on my own rig when possible, losing that much oil I'd guess you still have plenum issue.


Your issue may go deeper than mine ( hopefully not!) but with mine it was the spark plugs. They didn't look to be so bad imo, but swapping in new ngk coppers on 6 and 8 is what solved my misfires, I bought the full set so followed up and replaced the rest as well. I first had replaced the distributor cap (brass contacts) and rotor too though that wasn't the fix after clearing codes. They didn't appear too too bad but guess my van was demanding it is tune up time.

Check and replace distributor cap and rotor if you do a lot of driving, copper plugs are inexpensive so try replacing the 2 and see where that gets you. Might even try swapping plug wires from opposite side for good measure if all else fails.

the truck guys here are a good help but thought I'd ad my nonsense since I'd had same type of trouble recently