Just bought my first Discovery a few months ago. Pretty rough shape, previous owners neglected her ... Still starts every time and gets me to and from work every time, even under foul weather conditions! 1998 50th Anniversary edition. Fully loaded. Dual sunroof/moonroof.leather interior. All power options. Brush guard. New shocks, new springs, new slotted rotors, hid headlights, 2" suspension lift etc. Has around 194k. V8 AWD, Automatic. Typical power steering leak. Differentials currently not functional (probably rusted up). Might need radiator serviced. Wiper motor not functional. Washer fluid not functional. Needs an alighnment. May need new u joints, ball joints and tire rods. Needs new steering damper. Abs and Srs lights are on. Currently check engine light is on and cylinder 6 missfires when under load. And interior needs some work. Etc.

Started out with changing the oil and filter (was nearly empty when I bought the rig) and using Castro GTX high mileage, and a quart of Mystery oil per every oil change. Replaced the air filter (old one was melted and black!). Replaced the spark plugs and wires( some of the plugs looked burnt out). About to get the fuel filter and transmission filter replaced. Also used seafoam. Etc. Tuneup aside now I need to focus on the engine compartment. Had Autozone hook up the computer and the following codes poped up: p0306 ( cylinder 6 missfire), p1179 (fuel air metering) and p1316 (ignition system control malfunction or missfire). All these codes are manufacturer codes I believe. So I purchased a replacement ignition coil ( yet to be installed) and got a compression test done on the engine at DAP Enterprise, these were the results:
Cylinder 1: 120 psi
Cylinder 2: 150 psi
Cylinder 3: 120 psi
Cylinder 4: 90 psi*
Cylinder 5: 130 psi
Cylinder 6: 130 psi
Cylinder 7: 130 psi
Cylinder 8: 130 psi
* once a wet test was performed on cylinder 4 the psi went up to 130

The mechanic suggested a complete new piston kit, headgasket kit ( while down there) and complete rod bearing connecting kit, plus replacing the cylinder 6 ignition coil. A lot of work, a lot of hours and most of all a lot of money. If I were to go this route I'd probably have all fuel injectors and the rod replaced as well. But as it is I do not know what I should do: get the needed repairs done in intervals or save the money and get a new or remanufratured engine. Or upgrade to a more power gasoline engine or convert to diesel. So what does the land rover community have to say about this? I'm not rich and any such repairs would take months to get done as I only bring home so much from work, not to mention I'm a freshmen in college!

Part of me wants to start over, sell the rover and get a more fuel efficient car to save money, then down the road get another Discovery in better condition. Add the suspension upgrades and be on my way, but then again I really feel attached to my disco and want to restore it... Please help.

 

Return the coil you bought.
Buy Magnecore plug wires and NGK copper spark plugs.
Do short oil changes for the next several, by short I mean every do 2 at 500 miles, then do 1 at 1,000 miles and then go 3,000 miles.
These engines like 10w-40 and really like 15w-40.
If you use the high mileage or the diesel oil they both are high in detergent and will help to clean the engine and free up any sticky valves.
Stay away from Fram oil filters, NAPA (Wix) is one of the top rated oil filters you can buy, Purolator is the other.
No need to rebuild the engine if it runs well.
Start with the plugs are wires, clear the trouble codes and see which ones come back.
If you use cheap plug wires you will continue to get mis fire codes.