Hey guys well I am new to this forum, long time rover fan. Owned a 97 Disco (with 250,000 miles at time of totalization) and a 96 Range Rover. Now I have purchased a 98 Disco for fun that I only payed a couple grand for. Anyway,I am going to replace all the spark plugs and wires because the plugs are all loose except for one. Also I noticed the Tach bounces all over I mean by like 1000 RPM's and though the engine runs a little rough it is not that bad. Could the loose plugs cause the rough idle?Anybody had this experience before with loose plugs? Any other ideas on what I should check? I am going to flush the engine and run some high grade oil through. Any help or ideas would be most appreciated, trying to make this one last over 200,000 miles too.

What do you mean by loose plugs, can you not tighten them up? If that is the case you have some BIG $$$$ problems in tah the heads will either need to be retaped or replaced.

I had simaler symptomswith my 98 Disco. After messing with all the ignition components it still continued to sputter at times with the Tach jumping all over the place. A very good mechanic finally figured out it was a bad driveshaft speed sensor. This might be worth a look. My Discovery has 208,000 miles on it and it is still going strong.
Hope this helps.
Gtlux

Mike,

In reference to your question, they are loose like they jiggle a little bit when i touch them. They can be fairly easily tightened but I have not done this since I am going to replace the plugs and hoses on Thursday. Is that what you meant was a jiggle or did you think I meant they would fall out? Cause they are still stuck in they just wiggle.

I believe what Mike is asking - Are the spark plugs ( which screw snugly into the aluminum heads) themselves loose & wiggly? Or are the connectors (boots) loose?
If it's the spark plugs, then I wouldn't even start the engine again, unless checked by a TRUSTED mechanic. You have options, but limited w/out pulling the heads.
The only reference I'm aware of to the tach bouncing is when the alternator is malfunctioning (or wearing out) as I understand it drives your tach.

The wires are tight on the plugs but the spark plugs are not screwed in all the way so they are loose. I tightened the ones I could reach and there was less of a problem.

I would assume that when you say "I" you are doing the work.
Take it for what it's worth, but I would'nt even start the engine w/out resolving EVERY loose spark plug issue.
The heads that the spark plugs screw into is aluminum and will NOT tolerate the insane combustion pressures for very long w/ loose spark plugs.

You might ask someone else (mike) to weigh in on this, unless you have a crapload of time/money.

There are remedies if no damage was done yet,(some simple) but I can't type so I'm going to step back, Good luck, Greg

That is a HUGE DITTO!!!!!!!!!!!!!!!!!!!!!!!!!!

Okay guys, so tommorrow when I replace the plugs and wires, what else would you reccomend I do while I have it all a apart? I am hoping that the new plugs will just tighten into place. It seems like someone just didn't tighten the old plugs enough because I was able to tighten the existing ones fairly easily and there was no wiggle or movement at all. So since I am replacing them anyway what else should I look for while I am down there? I really appreciate all the help I have already receved here so thanks for that too.