Wanted to post my entire debacle complete with resolution for anyone who had read my threads in the past. I had been fighting a high idle issue for what seemed like forever, hadn't had much time to dedicate to it until the other day and I finally got rid of it.

The whole sage began months ago when my discovery developed a high idle out of the blue. I figured as most do that it was the IACV, so I bought a new one. Installed it, nothing changed. Took it to a local Rover mechanic who reset my adaptive values (so he said) and told me I had a valley pan leak that needed to be addressed. I was considering letting him take care of it because it drove me nuts, but I wasn't going to pay $700 just to replace the valley pan gasket.

I fiddled around with mass amounts of ether and carb cleaner, I could not find the vacuum leak he claimed was there no matter how hard I tried. This left me thinking that the issue he said was there didn't exist.

I replaced every line under the hood and still, nothing changed. Cleaned the TB, cleaned the MAF, checked and rechecked every sensor I could find and still found no issues. During this entire thing, not one code popped up and live diagnostics showed no faults anywhere.

Anyway I got irritated and started searching around and remembered what I had read about Spike having the same issue and replacing all kinds of stuff. I went to the junk yard and got the entire upper plenum complete with sensors and a matching ECU from a wrecked Discovery. Had to get a new battery too because mine bit the dust from sitting. On a side note, Pep Boys has now given me 3 replacements for the POS Bosch battery I bought less than 2 years ago.

Yesterday I replaced the upper plenum, all of its sensors and the ECU with the matching set from the wrecked Rover. Started up and runs flawless now, probably better than it has since I've owned it. The leak I almost paid $700 to fix was obviously not there to begin with, I think someone was just trying to pull a fast one on me.

I'll never know what actually caused the issue but I'm going to assume the adaptive value reset was never actually performed, that's all I can figure. Just wanted to toss that out there for anyone experiencing the same issues, always check and double check things and don't be so quick to trust someone.

 

Never reset the ecm is my guess

 

Glad you got it resolved, but in all due respect, that wasn't a very helpful post for helping others fix the problem. Basically the mechanic 'could' have been on to something, and maybe it was an internal intake leak or something along those lines which you wouldn't necessarily pick up with Ether.

What would be interesting is if you went back and swapped the sensors from your old plenum one at a time to see if the problem reoccurs.

At any rate, glad you got it running well again. I'm sure it was frustrating. I've got a very similar thing going on with my Jetta TDI right now and all the things the mech said were the problem turned out NOT to be the problem ....after a lot of $$ later.

 

Let's give it time see if it returns after a few months, if it does eventually you will find what is causing you to trip hi idle

 

The only thing he was onto was the wad of cash in my pocket, I'm no master tech but the guy was full of it. The leak he claimed was there was in the valley pan and he picked it up, or so he said, with a few blasts of carb spray. I didn't repair this "obvious" leak yet the problem went away, that goes to show the leak never existed.

I've swapped sensors around along with a million other random parts just trying to make something change, nothing happened. The only thing that cleared up the issue was the change of ECU and the install of sensors that came off the same vehicle. Nothing else did any good, if there was a mystery leak, it would still be there. Believe me I tried everything possible to justify his diagnosis just to avoid admitting I was BS'ed, the only thing that ended up making sense was that the ECU was never reset. I couldn't trick it into doing anything and couldn't replicate the condition no matter what, it bugged the crap out of me.

Mainly what I was getting at is don't trust someone when they say they performed a certain task. Dude was going to charge me $700 to change something that wasn't even the problem. Everyone told me to have the adaptive values reset, so that's the procedure I followed. I had hoped I wouldn't get jerked around but I didn't have an AutoLogic to go at it myself. I pretty much had to trust someone who was trying to screw me.

Basically it's worth it to chase it yourself unless you can personally perform the reset. There aren't many trustworthy mechanics left.

 

I get you, my local dealer charged me for the reset then told me they could not do it I drive to va pop the hood to check fluids and see metal shavings , I then realized they did what I insisted they not do , drill the plug and turn the idle screw

I ended up buying a pluenum and ecu also, then everything was fine for a while, tripped high idle then would not run, found I had an intermittant short in the TPS voltage, the ecm won't just go hi idle something caused it

 

Check wiring for tps. I think it is just a magnet on-off internally, so it may not test as being bad. If I'm wrong please correct me.