Land Rover Repair: 1995 Disco, throttle position sensor, vacuum leak

Question
John,

I have recently purchased a 95 Disco with a 3.9 V8.   I'm  currently having two issues:

1. The engine doesn't idle well when at a complete stop.
2. There's a loud popping sound when shifting between reverse and drive.

Your help is appreciated,

Doby

PS:  I love this truck, I'm hooked.


Answer
Hi Doby,

The rough idle problem could be a few problems.  You could have a vacuum leak, it could need a tune, timing may be off, crack in distributor cap, rotor worn, sensor related problems.  Does your Disco issue any CHECK ENGINE codes?  Check under the passenger seat if this happens, you'll see a small box with a digital display and the code will appear there.

My '95 Disco had a terrible time with its idle.  It turned out that the TPS (Throttle Position Sensor) was the root of all evil.  Trouble was, I spent over $2000 to find this out...

Something to consider is that our Disco engine is more DIY friendly than all the newer engines.  We can advance the distributor to adjust timing while GEMS and BOSCH engines cannot. We can also You can set base idle and can trim the mixture with the adjuster on the air meter.

As for the popping sound on the shift between reverse and drive, you'll definately need the help of a tranny expert. LR would find the problem faster but it will cost you more.  I'm not sure what would cause that problem but I'll ask around and get back to you with any info I find.

I hope this helps,

JohnMc