I've been getting weird idle again like it wanted to die on me and sometimes has .It would idle back and forth between 550 rpm and 900rpm. When I drive it and break the idles go too low to the point that my car wants to turn off unless I rev the engine. I replaced the fuel filter and cleaned the MAF. After doing that I would rev my engine and Everytime I did this the idle went from 900 to 700 or 600rpms. Idk if that solved the problem or if the problem is even fixed. But I would like some info on this idle issue. Also does the fuel filler neck and purge valve contribute to this problem? I have a 1997 land rover discovery series 1 4.0 v8.

 

1. are there any check engine codes ?
2. have you removed and cleaned the Idle air control valve , and cleaned the throttle body ?

 

there was but I erased them. I cleaned them out and now it's on 600-700 rpms idk if that's normal. I'm going to drive it around and see if it gets to turn off on me. Also do you know we're the purge valve is located at that one of the codes I remember idk if it contributes but I have to get that replaced. One more thing what are the tubes or lines that connect to the fuel filler neck?

 

Purge valve is mounted to the charcoal canister. There's a thread right here on the first page about the filler pipe and all, it has pictures too.

 

650 - 700 is spot on. Your truck is demonstrating some of the same behaviors mine did. Cleaning the IACV (idle air control valve) and throttle body helped, for a while.

My truck would simply stall at the end of exit ramp, and eventually would not hold idle under any circumstance, but would run just fine down the road. Stopping at a light was an adventure.

The IACV is notoriously sensitive. I've read many time that you should NOT change the position of the pintle while cleaning it. There are reports that the ECU (engine mgt computer) will need a re-flash.

I replaced my IACV with a unit from Napa auto parts (# CRB 21856... from a 4.0 L Jeep) for about $55 (get a new gasket too) rather than the expensive LR part which will run you $175. Again, some have reported that upon replacement their truck would not idle properly until the ECU was re-flashed. I was fortunate in that all I did was pull the pintle on the new unit to approximately the same position as the old unit, installed it, and was good to go.

 

thanks for the information. I think I just replace the IACV since I have life time warranty. As for the ECU, how do I re-flash it? Is it something I could do myself?

 

Need the LR software... typically means a trip to the dealer.

 

Find an independant Land Rover shop or one that works on Euro vehicles. In the olden days it would take a Textbook T4 to set the IACV (it screws in or out automagically to set length), now it can be done with an Autologic hand held which they should have at most indy shops. You can try to do what Walt did with his if you still have the old one, compare the pintle lengths and adjust the new one to the old one.

 

My son just replaced mine (it's his truck now) and did the same thing Walt did, manually adjusted it and it idles very smooth and starts right up no matter how cold. I told him it needed to be replaced since I had soldered the four wires like five times, it was the original. I can fix things........ one mans junk is another mans obsession.

 

Hey Walt, just had the surgery, inside feels new. Almost two weeks now and it's still somewhat swollen around the knee cap where the incisions where made. Two more weeks of recovery. I can bend it about half way before it gets tight. They took before and after pics. My meniscus looked like a fractured green stick chewed on by a dog. The surgery lasted an hour and half. The doc did say I have the cartilage of a 12 year old girl though, I told him I had nothing to do with it.......