Question about 1988 Land Rover Range Rover
On a cold start, whether it has been sitting for a few hours or overnight, after i start her she will run fine for a min or so then the idle goes from smooth to rough, vibes bad, and almost no power you floor it and is steadily but slowly revs up.. if you try to drive the idle drops more but will drive. it acts as a perfectly fine motor with no power i will floor it and she will slowly but steadily accelerate.. it will do this every time consistently for about the first 20 min or so of drive/run time then it will kick back to a nice smooth idle and run just fine.. i am clueless
This is listed under Range Rover and not Jeep Grand Cherokee ? So I take it you are refering to RR County or similar Range Rover.
Firstly I am assuming this a 3.5 V8 EFI flapper type. Some of this will not apply to the 3.9 which is not a flapper type AFM. All HT leads, plugs, dizzy cap filters been checked ect? No water loss, or oil loss ? Good....
Second assumtion you are in the UK or Europe, if you are in the US will need to visit www.rangerovers.net who may know of more local help :)
The trouble with the EFI system it is sensitive, if not correctly set up. Check your throttle cable is not sticky, and then you need a multimeter with millivolts on it and access to a CO2 meter.
You will need to check the Potentiometer, this sits just behind the AIr Flow Meter. With the ignition on but the engine off you can test the meter. You will need to check the CO2 out put too, this is adjustable.
Once you have sorted this you can sort the dizzy and idle speed, it is important to do this the right way round as ECU is very basic, do not forget this the last millenium kit we are talking about.
Idle speed is the mostly cause of this type of problem, other wise we are talking injectors and that is a whole different ball game. You could try a jar of Wynns cleaner ?
The short cut is to use the little thumb wheel on the throttle cable near the bulk head to adjust the idle, this can get knocked if you been doing other stuff. Just turn it when the engine is running being carefull to avoid any contact with HT leads, etc. It amy take a couple of goes, put the idle should be 600 rmp and 1000ish when the choke kicks in.
There are plenty of downloadable pdf fies to help with this
or CDs at
Posted on Feb 19, 2010
Could be ur o2 sensors emissions or catalytic converter clogged
Posted on Feb 06, 2010
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Posted on Jan 02, 2017
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