Hello all,

Firstly, this forum is AMAZIN! thank you to everyone thats helped me along the way with my new disco 1. None of you know you've helped me out, but all the great content on this site helped me get my truck running!
Now I'm stumped. Hoping for some good insight!!

Okay, here we go:
1999 Discovery 4.0 V8
220k on the clock, about 150k on replacement engine
wasnt running when i bought it. Blown head gasket with any additional mystery items.
Got it running! feels strong!

However. Two things of concern.

1) U Joints
Am I correct in thinking that theyre not as big a concern for Disco 1 owners? Should I replace them/service them (if they are serviceable). I dont really feel any vibrations. I do hear a faint "rubbing/ friction" sound as I drive. Cant tell where its coming from, but the faster the car drives, the faster the sound gets. You have to really pay attention and listen for it. With the stereo on or driving with window down, you can hardly hear it, or at all. Also, sometimes there's a clunk, when switching from Park Drive Reverse. I know U joints require regular servicing, but what are the big driveshaft/line differences between the Disco I and the Disco II?
2) Misfire
P1178 Maximum Positive AMFR Correction Fault
P0300 Random/Multiple Cylinder Misfire Detected
P0308 Cylinder 8 Misfire
P1316 Misfire Excessive Emissions Fault

Like I said; the car starts and runs great. No overheating. No dramas. Sometimes as I rev it in park and then when the rpms comes down, I can hear a little backfire. Nothing extreme.

Here is the list of repairs I've done:
New antifreeze hoses
New thermostat
New fan clutch
New Oil cooler hoses
New head gaskets (both)
New head bolts (yes, torqued correctly)
New valve cover gaskets (both)
New spark plugs and wires
New oil filter/oil x2 (did two oil changes running 10w40)
New oil pan gasket (took off, and cleaned out really well, reinstalled pan)
New fuel filter
New air filter
Cleaned MAF sensor
New ignition coil
I am on my first tank of gas 91 octane with 1 bottle of techron in there and 2 bottles of seafoam

Right now, the misfire is my biggest concern. That needs to be sorted out to pass smog here in California.

Anyone have any other ideas?? What am I missing here (besides cylinder 8) ;-)

Thanks!!

 

Double check your intake is not causing an air leak, should be sitting squarely between the heads. Been there, done that, the heads are off just a bit on the pins and the intake doesn't line up between them. Did you have the heads milled? 1178 indicates a lean condition, too much air or you may have a faulty MAF causing a lean condition. Might check or replace injector 8, check your fuel pressure at Schrader, should be around 34psi at idle. One other thing about misfires, check your coils for arcing terminal to terminal, coils when old become brittle and can chip or crack at the posts.