Decided to make my own thread after not being able to solve my issues. I have seen many people suffering from this problem with no clear solution.

Long story short my car runs fine while driving, once I come to a stop the car shuts off.

Car
2003 evo, mostly stock, aem boost gauge and thats it. Stock Ecu. Got a new clutch with a lightned flywheel but I had this issue BEFORE I got the new clutch.


Symptoms All of these issues happen after driving for a while, NOT when I first start the car.
Shuts off once I come to a stop or push the clutch in after driving.
Car will not idle without giving it gas, after driving
Once it shuts off it will not start unless I give it gas.
If it starts, it will run like crap, under 1k for a little while before it idles normal.
Car throws NO CODES. None.

I've been dealing with this for a little while now. Mostly because it will magically go away for a while then come back.
Recently it seems to happen more frequently now, like everyday without going away. Not sure if it's weather related since it's colder now.

My average drive in the morning.
Start the car, sometimes it will idle high like a normal cold start, sometimes it will run like crap, sometimes it will idle low for a cold start at like 1.3. Car will drive fine. On the way to the highway I will get an occasional idle dip below 1k, but most of the time it won't stall.
Jump on the highway, drives fine. Boost good. yay.
Get off the highway, as soon as I stop, car shuts off. try to start and it doesn't. give it gas and it starts but won't idle. I usually have to hold my foot on the gas for it to idle.

One thing I have noticed is that when my car is working, while cruising, my vacuum will show -21 which appears to be normal. When my car is running screwy, while cruising my vacuum will show -22 ;/ odd, not that big of a difference but its definitely something.

Checked so far
Spark Plugs- Just changed. Car ran fine for 4-5 days then back to the same issue.
Vacuum lines - didn't find any lose or disconnected.
Iac- Unplugged, turned key, moves in and out. Voltage seemed fine but need to check again.
MAF - cleaned out with proper cleaner.

Help ;/ any ideas?

 

What dv/bov are you using?

 

MR bov. Stock airbox, turbo, exhaust, pipes.

 

Just thinking out loud, but is the MAF sensor plugged in all the way? Any of the intercooler pipes loose or leaking?

 

Yup, checked and checked. I have seriously taken everything apart and put it back together a few times.will update op, Also cleaned maf with a proper cleaner. but thx for the suggestion.

 

Try and double check all your vaccuum lines around your EGR valve and around the back of the manifold.

 

^^ going to do, yet again. pissed I can't see back there really. Funny thing is, I feel like it has something to do with how warm the car is. It only stalls out for sure once the car is fully warmed up. :/

 

Wish I had some advice for ya... My problem is nearly identical to yours except it doesn't seem to matter whether it's warmed up or not, and is completely random. I was told I might need to re-tune... Just out of curiousity, how much vacuum are you pulling at idle? I usually sit just under 10 inHg. Seems kind of low to me. Not trying to highjack, but seeing how our issues are very similar, information given here could benefit us both. Thanks!

 

Try doing a boost leak test.

 

boost leak test or also i seen it happen before the blade in the throttle body shifts and leaves a gap to let air in. which would cause to stall at stops or hard breaking. id also check that as well also just because all your vac lines are on doesnt mean one could have a slight cut or dry rotting.

 

I had the same problem, and checked the same things as you. I changed out the throttle body shaft seals, and noticed the old ones were entirely finished, they were torn to shreds. It seems to have helped so far, but I haven't driven enough to fully verify it.

A temporary fix would be to adjust the idle control screw to make it idle higher, but that's just a temporary band-aid until you figure out the real problem.

 

Have you clean the IAC and MAP sensor?

 

If you want to just do a full rebuild I would clean the throttle body completely, rebuild it with milspec seals and coat the engine side of the throttle body flapper with molycote (dry film lubricant) and that will seal it up but allow no sticking. New Throttlebody gasket + new BISS Screw + o-ring and that'll eliminate the t-body leaks altogether. Just be careful installing the Milspec seals.

Try borrowing a friend's MAF and or IAC valve (seperately) to test a difference. My IAC Valve was working when I pulled it out and turned the key however didn't work when installed.

 

You mean at idle? My boost gauge reads -18 when everything is fine.

How long has it been so far? I am about to go this route as well, just wanted to change the small parts first before i start taking crap apart. this is also my daily.
I thought this might be the case after it started happening more frequently with the cold weather. maybe more air is getting in there now than before.

On my to do list. Tried to make one a few wknds ago, sucked. Need a better sealant.

 

didn't clean the IAC and didn't think about cleaning the map.

The most frustrating part about this is that it's pretty random. Drove to work this morning, and it cut off when I got off the highway. Drove just now for my lunch break, all good there and back, perfect idle. :/