Ok, so I have now had my 03 Discovery for about 5k miles (59k total). When I got it, I noticed it had an intermittent drop/rough idle when engaged in drive. I have, since purchase, done the following: 1) run premium gas 2) done the sea foam treatment 3) checked for trouble codes (none) and 4) taken it to my local mechanic (no real experience with Rovers, but a good guy) to check the plugs and wires, no issue....So still some days the idle is rougher than others and it is not constant when it does happen. The tach is showing around 750-900 when idling in drive, and when the fluctuations occur the tach DOESNT move. When engaging into park, the idle goes up to about 1100 and the roughness pretty much goes away.

I have searched the forums for rough idle, hence the premium gas and sea foam. What would be my next move? Shouldn't I have a trouble code ifthe idle is that noticable?

One other thing....when engaging into drive and barely giving a little gas (moving around 5mph) there is a slight sputter, almost like gas isnt being delivered properly....could it be related?

What do you guys and gals think?

 

Plugs and wires: There is no reasonable way to just look at spark plug wires and tell they are good. Get Magnecor 8mm wires and Bosch +2 plugs.

IAC/Stepper motor: This is the cylindrical electric motor on the top of the driver side intake manifold with one tube coming from the intake tube and the other going into the manifold just after the throttle body. Unplug the connector from the back of it and take it off.

Buy a can of carb cleaner and spray all of it into both sides of the motor (both holes where the tubes attached). Mine did not move freely until half a can was sprayed into it. Use a wrag and clean it as best as possible, shaking it to get dirt and cleaner out of it. Let it dry for a few minutes before reinstalling it.

Now it should idle just fine, near 650 rpm's +-50 rpm's.

Cheers,

Pete

 

You need a tune up. New spark plugs and plug wires. Now here is where it sucks, you must use Magnecor spark plug wires. you can use any spark plug you want but you must use those plug wires.
www.atlanticbritish.com

 

You need a better mechanic, one who knows Rovers a little better.

 

Bingo~

 

Alright. So I made an appointment with a local guy (The SportsCar Shop) here in Eugene, Oregon. He specializes in Rovers, and a variety of British imports. Considering his shop rate is up there, I want to try and have this narrowed down as much as possible. I know there is no way to count out the plugs and wires, but the others I can. Since the throttle body has been cleaned, premium gas run through, Sea Foam done, and the cat has been checked. Can someone attach a pictureof the IAC/Stepper motor? I will attempt to clean mine out before I drop off the vehicle on Thursday. I can do most do it urself type jobs, but am no mechanic. Attaching a pic will ensure that I am unhooking the right part...

Don't laugh....you all had to start at one time.

Thanks for the posts, I have my fingers crossed that it is only the plugs/wires...yes only the plugs/wires...

again...thanks

 

I dont think that a DII has a stepper motor. I could be wrong, but I cannot find one anywhere on Atlantic British's web site.
But here is what one looks like for a DI.
http://www.roverparts.com/Parts/ERR4352.cfm

 

This is the stepper motor.

Most auto shops will see you pull up in a Land Rover and their eyes will light up with $$$$$ signs. I would avoid them like the plague. As far as being mechanical, everyone has to start somewhere, including you.

Order new wires and plugs (the ones we all mentioned earlier) and spend a Saturday wrenching on your Rover. You'll get to know it better and have more confidence in its reliability.

Cheers,

Pete


[IMG]local://upfiles/10333/28F2984FF7C1400A84799B3FDEDCC8D7.jpg[/IMG]

 

See, I told you DII's had one.

 

Having a Scangauge really shows you what your engine is up to.

After cleaning my stepper motor and running a full can of Seafoam through a vacuum line, my idle fuel consumption dropped from 0.4 gph (gallons per hour) to 0.2-0.3 gph. This is pretty significant considering what little things I did to clean the engine and make it run better.

Cheers,

Pete