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KeithElisa November 28th, 2003 10:54 AM

fluctuating idle
I have some strange idle problems with 97 D90. My idle keeps dropping so low the engine cuts off. It comes and goes off and on. I have changed the fuel filter and the air filter and pulled out the air idle valve and cleaned it. Anyone had this problem or have any advice?


Mike Hippert November 28th, 2003 03:43 PM

If you have not checked it out yet look here. I had a similar problem, the plugs on the distributor cap were corroded. I also ran some injector cleaner threw the system and the problem went away.

evilfij November 28th, 2003 04:42 PM

Replace the Crankcase breather hoses. They are plugged and contributing to the fault. Next check the vacuum lines. Also make sure you are not low on oil.

If this does not help you have an issue with a sensor out of spec so you will need to trouble shoot further.


Mike Hippert November 29th, 2003 08:20 AM

Keith, I like the Avatar! who is the young driver.

Mike Hippert November 29th, 2003 08:22 AM

doh! double post!:mad

scot November 29th, 2003 03:03 PM

Another possibility is the stepper is part of the gizmo that sets the idle, and I have had one go bad before. I don't know if that is the same part you describe as the air idle valve, but it could be. My first truck behaved exactly as you describe your problem. They (stepper motors) can be removed cleaned and lubed if they are failing and sometimes they will work well for another year or so. But as I said...I ended up having to replace one...which sucked. I can't remember how much I paid but it was a few hundred dollars.

KeithElisa November 30th, 2003 06:09 AM

Mike, That would be my son and future land rover driver, Colin. He's just turned one. My 3 year old daughter Leah loves rovers also.

mikeslandrover December 1st, 2003 04:17 PM

Air flow meter is probably at fault

KeithElisa December 2nd, 2003 01:43 PM

Where would that be located?


nmarkiw December 5th, 2003 12:08 AM

I assume from your profile this is a 97. GEMS. Is the check engine light on? Has the battery gone dead or been disconnected recently? If so, the adaptive variables may need to be reset. (Requires a Rovacom/Testbook/T4) The TPS could be out of adjustment or faulty. If the TPS is not below 13%, the GEMS won't control the idle. This can be tested with a volt meter.

A generic OBDII scanner can verify these.


KeithElisa December 5th, 2003 06:05 AM

Yes, it's a 97 and the check engine light never came on. But I do have a battery disconnect on my ground terminal that I keep disconnected for up to a week at a time. The reason for the disconnect is I have a mystery battery drain that I could never find.
I don't have a test book or a scanner. I hate to go back to the dealer they never seem to find or fix anything but I think this problem might be out of my league. I do have a volt meter and a shop manual.


Doug December 5th, 2003 11:40 AM

Post on the forum, and Mike Green will give u some ideas I'm sure -- he is a genius IMHO.


kkaiserblu May 29th, 2006 01:46 PM


I was wondering if you could show me or tell me where the steppor motor is exactly?

redrover May 29th, 2006 03:08 PM

1 Attachment(s)
X marks the spot. JP

Hoss May 29th, 2006 09:07 PM

My money is on the stepper motor. When it is faulty you will get a fluctuation that sounds like your issue. The part is not cheap, but it is an easy replacement.

Good luck with the fix.

Heath May 31st, 2006 07:38 AM

I have had problems that were related to the speed transducer. The transducer did not throw a code for a long time... it threw a lambda sensor code (44 or 45 i think). I did switch the idle stepper motor, several hoses, and tested throttle position sensor, set base idle, rotor cap, distributor coil (with mallory unilite), and the o2 sensors.
All of these things can cause idle problems. Could it be related to speed. When you slow down? Randomly? And as for the stepper motor, you can get one from NAPA.

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