My wife's 91 Disco II which is a curse someone wished on me, is stumbling between 42 MPH and 55MPH. On rare occasions it starts earlier or finishes at a higher speed...but very rarely.

I changed plugs last week and it needed it.
I have wires on order but this doesn't feel like a wire.

It idles beautifully and accelerates extremely well and cruises at highway speeds smoothly.

I can accelerate through the stumbling and it has plenty of power.

It has been throwing misfire on cylinder 1 and random misfire codes and a 1590.

I have the three Amigos but have had them for a month.

Today, I cleaned the TB. It actually helped but the stumble is still there.
I did an induction cleaning. I didn't notice any change.

I had a cheapie Scanner so I bought an actron cp9580. I cleared all the codes and then went for a drive. As usual, it stumbled and when I checked trouble codes, it was the 1590.

When I used the code connect feature, it suggested replacing the MAF as number one and replacing the 02 sensor as number 2.

The 1590 seems to be one of those Land Rover secrets but I thought it had more to do with the three amigos than a misfiring engine.

Any ideas, suggestions?

 

1590 is your 3 amigos and has nothing to do with your misfires. I would suspect bad wires but it is strange you are not getting misfires codes. Otherwise I would suspect maybe a bad fuel pump. O2 sensors would not cause misfires and a MAF would give a code.

 

Thanks Lipad!
Figures it'd be a mystery problem. I just can't tell you how much I hate that thing...all the way from the dealer to the lug nuts.

There isn't much more I can do until the wires come in next week. I ordered Kingston 8mm. I am not looking forward to putting them on. only Land rover can make a ten minute job take 5 hours.