I'm having a small issue with my 06 IX MR. whenever I go WOT, the car pulls but then seems to bog down, stumble at high RPM's. it doesn't do it everytime, and it does it in different gears. if it's doing it and I let off the gas, then get back on the gas, it goes away. or if i shift to the next gear, the car begins to pull again. i've watched my boost gauge while the problem is occuring, and the car seems to hold boost. i'm thinking it may be something to do with the fuel system, possibly ignition (spark plugs, etc), or maybe even the intake system? I dunno, haven't had time to trouble shoot yet. anyone got any ideas?

the car's engine is stock other than Sparktech COP, drop in filter, and HKS exhaust, no tune.

 

-Do a boost leak test
-log it, with a wideband if you can
-swap spark plugs/wires/coil boots
-run some fuel system cleaner through it, 1 bottle of cheveron in a full tank

good luck!

 

boost leak was my first thought, but according to the gauge, that's not an issue. I am replacing the upper and lower IC piping, couplers, and all the clamps to t-bolt clamps, changing the throttle body shaft seals, and injector seals within the month so that should take care of that.

I really hope it's not the damn coils. those things were like $600, and I've only got like 40k miles on them. I'm going to take a look at the plugs to see if they look bad, and probably replace them early. they've only got 40k miles on them too.

already did the fuel cleaner, but I'm thinking about replacing the injectors, and the fuel pump to replace the filter.

thanks for the suggestions. I've had/done those ideas, I'm trying to think of some things that maybe I hadn't thought of yet that might have something to do with my mileage.

I don't know much about my MAF sensor, but if it were going out, would it cause this issue? also, are there any other sensors that might cause issues like this?

thanks in advance for the advice.

 

if its a heavy hard shut down sounds like a boost leak to me. your gauge will still reach the desired boost but your turbine is spinning like crazy to reach it. check your AFR - i bet you are rich as effff and hitting fuel cut.

a hesitation or slight stumble is most likely spark. check gap, and or change plugs.

good luck!

 

ahhh, thanks a lot man. i'll try to do some trouble shooting tomorrow. it does seem like it could be a boost leak, but I was misled by my gauge. I think it could be a leak because it seems to happen when the car starts to hit full boost (duh)... I'll do some checking tomorrow. I'll try to eliminate that possibility before moving on to the plugs.

 

I would check the plugs. When I use to hit full boost on my 2G the car was breaking up really badly and I asked on the forums I was told its for sure boost leak. I was hitting full boost but had to let go since she started to miss. I say check for leaks but pull the plugs and check the gap on them. Replace them, make sure the gap is good and than take it for a ride. You have any codes?

 

The turbo will compensate by spinning higher if there is a boost leak, you will likely still hit target boost, but your Mac will be reading all of the extra air that's not ever making it to the engine.

Do a static boost leak test, while the car is not running, in your garage.

 

Damn your car has alot of miles!! Im not too far behind you.

 

Change the plugs, they are cheap. Also check your alternator if the cars wanting to stumble it may be losing power.

 

Hmm, $600 on a COP setup on an otherwise stock engine with "no tune". Could've saved some cash and just got it tuned. The stock ignition is good for quite a bit of power, definitely good for the minimal mods that you have.

I do hope you figure out what's going on, having high miles like that would make me paranoid because it could be so many things.

 

You can never judge whether you have a boost leak fully by the gauge. When I troubleshoot a turbo'd car, the first thing I do is a boost leak check. Probably the main cause of most problems as it is. My hot targets would be a TB shaft leak, torn coupler/loose clamp, or the pesky vacuum lines on the EGR (check that out first, just reach down there and feel for a popped off hose, follow the lines on top of the TB to the EGR).

If not, try plugs (I've got some killer Iridium prices) then start looking deeper into the fuel or igintion systems.


You have no idea how much a COP kit from any of us vendors can transform even how a stock car drives. For one, it greatly reduces or eliminates flutter and smoothes everything out.

 

Put plugs in it first.

 

how do you have 3k posts and not know that you can't tell if you have a boost leak or not based on the gauge?

It sounds like an ignition issue to me tho. cracked plug, carbon tracing, dead coil ( yes i read you have sparktech, but no one is perfect). See if you notice it get worse with more engine load like getting on it up a hill in a longer gear than you should, basically lug it at full boost. Also pay attention to if it gets worse when its humid or rainy, that would be another thing that points to ignition.

 

could be your fuel pump starting to take a crap.

 

check your injectors, and make sure the seals are still good and the injectors are flowing enough fuel.