Land Rover Repair: 1995 Range Rover - Idle adjustment, throttle position sensor, throttle linkage

Question
Dear Mr. McInnis,
I have a 1995 Range Rover 4.0 SE.  Currently 88,000 miles.  On start up, the engine runs rough and will stall.  Once warmed up, it runs fine.  My tach reads 250 RPM at idle while cold and warm, this seems low.  Is there an idle adjustment to increase the idle RPM's and what is the proper setting?  Also, where can I obtain my radio security code to enter after having disconnected the battery?

Thanks,
Dave

Answer
Hi David,

my '95 Discovery 3.9l idles at 750 rpm.  This is normal.  I would imagine your is about the same.  There is no normal means of adjusting the idle speed.  Usually this is controlled electronically.  Some owners have been known to play with the throttle linkage but this is not how it should be done.  I've seen the TPS (throttle position sensor) with faults and it can also affect idle speed when it begins to fail.  Perhaps you should consider some maintenace (ie. plugs, wires, filters) unless this has already been done.  You may also want to have the engine diagnosed by a reputable mechanic with a LR testbook.

It is rare for a 4.0 to have a problem with idle air control module but it can happen.  You can buy the LR part for about $300 or try the NAPA replacement part (Echlin #2-1856) for $52 (a tip from a fellow Rangie owner!).

The security codes can be obtained thru your local LR dealership.

Best of luck,

JohnMc