96 Disco Revs High

[robertmazur]

I have a 1996 Discovery (about 130K miles) that was running wonderfully. Beginning a few weeks ago, it idles at about 1750 rpm consistently, from initial startup to shutdown. Putting it into gear brings it down (and slams the transmission). But whether hot or cold, the idle while in park stays around 1750rpm.

I loosened the throttle turn-screw as much as possible, but with no effect. What else, as a lay-person, could I check for?

Thanks,
Rob

[Les Parker]

Hi idle

Hello there,
Is yours an auto or manual transmission?
Also have you had the battery run down recently?
Does the alternator "whine" or "whistle"?
I've had similar issues with my 97 D I and it is looking like the alternator is is the culprit, though I'm going to check with our Supercan tool (DEC II) to confirm this.
Please advise on the info asked for above,

Regards

[robertmazur]

96 Disco Revs High

It is an auto transmission. The battery has not been run down lately. The alternator does not whine or whistle. I am sorry to say that it does not exhibit any odd symptoms other than the high idle. Kind of wish it did as that might give me a clue of what is going on!

Rob

[singingcamel]

clean your stepper motor, un plug it from the rear plentum passesnger side.
clean it with carb cleaner. watch that gasket,it can be a little brittle..

[shireyd]

i've seen the area where the throttle butterfly in the intake manifold can be dirty . just when the butterfly gets to the point to close it gets the dirtyest . with engine off.. pull air intake hose loose from intake ,look inside at butterfly and with your hand or some helping hand open the throtle so you can clean area at the point which it closes. this dirt buildup can keep throttle from closeing all the way. . carb cleaner and a rag works well

[SGFMORover]

had that trouble with mine for weeks before the alternator went. wasn't creating prop[er voltage at low RPMs so the truck held a high idle... can't maintain that idle whn put in gear so it clunks hard through any slack when you shift. test your battery but I'd guess alternator.generally the reason for the ECU to hold a high idle is to charge electrical.