I have a 1998 Land Rover LSE (4.0L V8) and recently I have been having trouble where the truck will run fine for days, and then out of nowhere (particularly in wet weather, although today is happened while its been sunny) engine won't rev past a certain point. Depending on the occurrence the point is different (ie 1500rpm, 2200pm, 1700rpm, 3000rpm, etc.) When you try to push the gas further the needle bounces, the truck starts to vibrate a little more, and you can hear the engine going "DO do do DO do do DO do do DO do do" (sorry, no other way to explain it. throughout trying to rev past this point, there are random knocks that can be heard very distinctly. Then, after restarting it, the point changes, either higher or lower, or goes away entirely. I mention spark plugs because with the engine running I went under the hood and touched a spark plug wire, and was shocked. If anyone has any advice on what the issue might be I would greatly appreciate it.

 

Wait until the vampires come out tonight in the dark, and look under hood with it good and dark, you may see small sparks. Any question about wires go with a new set of silicone 8mm high quality wires. Cracked insulation on wires and mositure don't mix. Sometimes coils can be cracked as well.

 

I remember the ONE TIME I touched a spark plug wire on a running engine, it was a 1967 283. Felt like one of those electric fences.

Guess that is why they refer to it as the High Tension Side. (After the coil) ^The coil raises the voltage level up into the thousands to have the spark jump the gap. Basic functio of any gas engine.

Never touch one of those wires with the engine running unless you enjoy the tingle.

In addition, it could be the Vehicle Speed Sensor going bad, if it thinks you are going
over 115 or so , it cuts out the engine to force you to slow down. If it goes bad, it thinks you are driving 115.

 

i touched the spark plug on my grandpa's 43 ****** jeep.........holy crap did I learn my lesson

 

Sorta like a taser without the barbs.

 

Be sure to lick your fingers prior to touching the spark plug wire for maximum effect.

 

If I remember right each spark on a car is about 60,000 volts.

 

that will get you outta bed in the morning

 

Back to his original issue, probably not even the spark plug wires, but good new ones never hurt unless you touch them with it running.

 

Walter, one of my favorite Jeff Dunham characters:

Pee break on Jeff Dunham Show - YouTube

Enjoy it. "Dumbass!"