I have a 2003 Land Rover Discovery II SE7. Recent work new plugs, wires, and a coil at the LR Dealer. When I start it if I give it gas it will start but if I let off the gas it will just die. It will do that three or four times until I keep the gas on and rev it for a minute or two. Then it seems to be fine. Once it's running it runs fine. Any ideas?

 

Idler valve maybe? Sounds like the same issue I had when my idler valve came unplugged. Try popping the vacuum line off of the back of the throttle body and then see if it will start. Don't run it that way long, but it may be a way to check.

 

Alex is the big brain but let me chime in because I had this same issue this very week. But mine was intentional (I was disconnecting sensors to see which ones the engine and transmission would run without).

The ones that killed the startup idle were the throttle position sensor and the idle air control valve. Both connectors are on the driver side, upper intake. Check those connections. A giant vacuum leak would do the same. But I'd think something would have to be totally open to kill it.

 

I appreciate the compliment, but I think you've got more experience than I do with these engines. Haha

I've never had the throttle sensor off. The clip that holds mine in place just broke. I really hope that doesn't cause me future issues. I know it will, but a guy can hope. On a side note, exactly the same connector as the crank position sensor plug which I also broke. I've still got an extra because Abran sent me two when I broke mine back in the winter. Might be a fun project one day soon.

 

My knock sensor clip broke. I don't worry about those things until they break and I realize they are in the freaking harness.

You'll know your TPS is off when it surges and almost dies at startup and then the transmission shifts harshly. M&S flashes and almost every dash light comes on, and the shifts all take place over 2000 rpms. What is alarming is that when you plug your TPS back in, it takes a long time for the lights to go off. Haha. Mad scientist work.

 

Damn! That's some serious business. I was expecting just another check engine code and a loss of throttle response. I guess I'll bump that one on up on the list of things to do.

 

As far as I can tell by seat of the pants the TPS just informs the transmission as a 'torque" input. The engine seems to run fine without it (except for the odd startup behavior and Christmas dash lights). But I only drove a few blocks that way. Abs and traction control go nuts.

Same for MAF. You're better off without one than with a malfunctioning one. Probably get 8mpg but can go.

Idle air is a go/no go (bad start, random misfires). Purge opens a huge vac leak when it is bad (stuck open) but not a huge deal when unplugged.

You know I'm building up to a swap! Apples and oranges! Fruit salad!

But I just hit the high bid on a 95 with a 200tdi and r380. Someone needs to outbid me. Quick.

 

More info that may help on this. Once it finally gets started and doesn't die it runs fine. No surges, no shifting issues nothing. When I come to a light and have to sit it idles fine. This problem happened yesterday when it was hot. I checked first thing this morning (it was dead cold) and it started and jumped up to around 1500/1800 idle for a moment or two then dropped down to it's normal idle. I will drive it some today and see if its a hot issue. I will post later today.

 

Okay more info. I checked all the vac tubes I could find all good. Checked fluids all good. Started fine when cold. Idles up for a minute then down to what appears to be around 750. Drove it this morning drives fine, no surging, no shifting problems at all. When I got home and it was warm (not hot) I tried starting it again. Started and idled at 750 then dropped down to 500 (kind of rough but not overly so). I started it up twice and same thing. Up to 750 then dropped down to 500. (the readings are if the first 1.0 is a thousand lol) Okay so it has set a bit and cooled down but not cold. Starts idles at 750 then drops down to 500. This definately seems like an engine idle situation that comes on when the DII is hot or warm. When hot it does what I originally posted and when warm as I said above.

 

That does seem to point to the idle air control valve. That is the silver cylinder on top of the intake that has two black hosrs, in a U, on either side, and should she a gray electrical connector at its back. They are quite expensive. It almost sounds like it isn't working. It's job is to help determine and adjust your idle. A vacuum leak (or at least, the ones I've had) wouldn't cause the surge at startup; my vacuum leaks have just make the engine run poorly from start to finish.

I would first be sure the electrical connector is fully seated.

Then check to be sure the hoses and hose clamps are tight and the hoses aren't cracked.

If everything checks out, unplug the electrical connector and start it up. See if there is any change. If not, that's your culprit. If it changes, then everything I just wrote may be wrong.

If there is no change, then you can try cleaning the valve. I've seen many do it on YouTube with MAF cleaner. I've never done it but the YouTube authors claim success.