I have a 95 discovery with 178K miles and recently changed the oil, plugs, wires, and O2 sensors. Was driving today uphill around 60 mph and something on the right side of the engine starts knocking. It would not down shift to a lower gear, even when i had the pedal to the floor. Seems to knock more when under a heavier load. It idles a little rough, but never stalls or comes close to stalling. I usually drive this vehicle around town and never reach speeds of 60+ mph, or put engine under load of a 2 mile uphill drive. I never have any issues when driving around town. I have no idea what to look for. Any ideas?

 

Go back and double check your work, you may have crossed a couple of plug wires or one or more plug wires may be loose.
Is the check engine light on?

 

I will do that. No check engine light though. Any idea where I can find a diagram or any info to help double check I have the wires connected correctly. thanks

 

With no check engine light that make it alittle harder to figure it out but because you just worked on it double checking your work is the first place to start.

 

When I say recently, I probably changed plugs and wires 4 or 5 months ago.

 

Now this changes things, if it were a crossed plug wire it would have happend that day.
What brand of plug wires did you use?

 

You need to spend some time under the hood and engine while it is idling to find the noise.
I would not suggest you drive it any more till repaired so you don't loose an engine.

 

Im sorry, I have no idea. I just bought what ever they sell at autozone. O2 sensors changed yesterday. The hill that gave me the knocking issue is the same hill that it barely made it up before changing O2 sensors.

 

Disco Mike----It doesnt make any knocking while at idle.

 

Well, I am not sure what to tell you other the 02's and a 3 month old tune up are not causing this.
May want to find yourself a good mechanic, and again, don't drive it til you can get it into a shop.