fixed

 

Still in the learning process perhaps? I had the same issue. Took a while before if finally settled down.

 

I dunno maybe your iac is failing slowly but mine failed completely. I tested it using the procedure in the shop manual and it failed the test.

 

fixed

 

My iac is jammed. If you take it out of the TB keep it plugged into the harness and turn on the ignition key without starting the engine. The plunger should move and the motor should vibrate to hold it's position. My valve didn't move or vibrate. It just started to get pretty hot since the motor is jammed. That's it really. Obviously there is a design flaw since it only lasted 55k miles.

 

Follow up on my high idle. Just installed a new IAC valve and all is good. The car idles and drives like new. No such thing as the idle needs to learn. Just started working correctly immediately. Shame that our Mikuni TBs have bad throttle seals and very expensive IAC valves that burn out.

 

fixed

 

If you do decide to buy a new one search here for a link to EBay. I payed $300 but found out later that there is an equivalent for $100 less.
Also make sure you don't have any loose or dry rotted hoses connected to the intake manifold. A small vacuum leak there can change the fuel pressure slightly also causing high idles.
I'm planning to dissect my old IAV to see exactly how it jammed.

 

fixed

 

try and disconnect the negative battery terminal wait 10 Min then test the iac again

 

I still say vaccum/boost leak.

I know it is annoying... but be patient, and make sure you cover all bases before you go and waste money on part you may not need......

Check and double check all hoses.... for vaccum leak

Do a boost leak test. I beleive I gave you a boost leak tester.

When I blew out the coupler on the lower ic pipe... I looked and looked for two weeks. I never saw anything until I built the boost leak tester. I charged the system with air, and I found it IMMEDIATLY

--Dave

 

fixed

 

sorry new here and looking for some help have an evo 9 mr running e85 and or 91premiun bought the car like that boosting 28 psi on e85 and 26 on pump had code po171 running lean performed boost leak test found my throttle shaft seal
leaking alot had another throttle body from evo 9 replaced it while i wait for seals
i ordered to fix the other throttle body ran leak test again no leaks my fuel trims came down to normal but now i only boosy max 22 psi and after i left off gas and
put in neutral my rpms stay up around 4k for a second or so then come down to idle i thought maybe has to be retuned not sure any ideas or advise would help
thank you sorry expl so long but im very detailed thank you

 

holy crap, look at when this thread was last active...can't you start your own thread?

 

Do you have a 03-04 E8? I know they are slightly different than the 05-06. Wondering if you hooked up something wrong. What condition was the E9 TB?

If you were tuned with these leaks present and you fix them all, would be a good idea to retune. Especially if you are pulling codes like that. I'd avoid boosting high if you can until you get your tune refreshed.

I did a boost leak test on my Evo Sunday and fixed two really bad leaks and ordered mil.spec seals for the leak in my TB. I noticed the gauge registers less boost now too. But take that with a grain of salt because I'm having waste gate issues too. Instead of 30psi... It's only 26 yay! *facepalm*