Could be your MAF sensor. Is it throwing any CEL's?

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I agree with Cosmo, sounds like something w/ the MAF. Check that first and report back. How long did you let your car idle for? Like will it idle for 5 min straight w/o stalling?

 

no cel. it will idle as long as i let it when i start the car. but when i try to accelerate it dies out and then it won't idle. iff i wait 10-15 seconds then start it then it will idle.

cosmo, i don't know if you remember back in december, or january the car would hesitate and pop if i was over half throttle. you said it was most likely the maf sensor. how often do they go bad. it has not ran right since. i have been driving easy because i could not go over half throttle, now it wont move.

i have the factory airbox with the water trap removed and a k&n filter that is about a year old

 

Pull it out and look at it. Two screws.

 

Pull it out and look at it. Two screws.

i did and it looked like normal. at least what i think is normal.

i replaced the fuel filter. it didn't fix the problem.

today i can drive the car but can't go over half throttle or it will sputter and pop, and the egt will go strait to 1,600

i went to subaru, they sugested that i get realy good fuel ingector cleaner. or the problem could be the fact that i have no cats.

 

The fact that you have no cats is completely wrong. Try the fuel injector cleaner.

 

alright!!!! the car is now drivable, but if the boost goes over 5 psi then the car shakes, pops, and the egt goes up fast. if i floor it then the boost goes to 14 and the car starts to slow down, and the egt goes to 1,600.

i have tryed cleaning the screan on the fuel pump, replaced the fuel filter, used some profetional straingth fuel injector cleaner.

does anybody have any idea what could be the problem.

one tech at subaru said " sounds like fuel starvation."
another said " sounds like it is running to rich."
another said " it is because i have no cats."
the last one said " seems like a cloged injector."

none of them have heard of a mas air flow sensor go bad.

 

also. i don't know if this will affect anything.

i have a header,uppipe,turbo back exhaust. no cats. i don't have a cel fix for the o2 or the uppipe temp sensor.

 

Mmm you might want to resistor the factory EGT sensor in hte uppipe. That is probably your problem.

 

what size resistor, what resistance.

by the way all my mods were put on in september, and it did not start doing this until january.

 

I think a 2.2 k resistor. I am not sure about that thouhg.

 

if it is 2.2k that's 65mW of power so even the smallest 2.2k resistor would do.

 

thanks. i will pick one up.

 

back again

ok now this car is pissing me off!!!!!!!!!!!! for the past year it has done this every time i take this car out of town.

this last weekend i drove 5 hours to north carolina. spent 2 days there with out issue. i was 2 hours in to the trip home and went to pass someone on 95, i hit about 70 mph. in 4th gear, 4,000 rpm, and the car pops, bucks, boost goes from 15 to 5 then to 10 then 5 and the exhaust temp goes past 1,600. it only does it past half throttle and over 4,000 rpm.

i put octain booster in thinking that i had bad gas ( how can somone get 10-15 tanks of bad gas in 1 year?) i cleared it up for about 20 miles then was back to the problem.

any one know what i could be. i have been told a vacum leak can do this but i have checked every thing and nothing is loose. and how do i only get a vacum leak when i go out of town.

some one help or this car is going off a cliff!!!!!!!!!!!!!!(j/k)

 

i was almost in a head on colition last night with my 7 mounth old son in the car. i was passing a garbage truck on a 55mph 2 lane road, and the car shut off in the middle of passing the truck. i was withing 2 car lienths of the on comming car before i was back in my lane, then the car turned back on. the truck was going 25 and it took me 10-15 seconds to pass i could not brake 35 mph in second gear. that was a long time. the car will not excelerate when it does this. all i could see in my mirror was a clowd of greyish black smoke.


OK now today it seems to be fine but yesterday it was half way drivable. when it was cold it ran fine, until it warmed up.

so nothing has changed between yesterday and today ( have not added any gas or additives) but it is running better.

i will guaranty that it will do it again. but nobody can help me! Subaru techs, mechanics, friends, wrxtuners.

 

WHAT Subaru techs could not help you!?! Dude im not sure with this one, have you kept up on normal maintance? Cleaned air filter...so on? How many miles are on it?

 

I would really tell you to have the maf tested with a multimeter amd compare it to factory specs. This would rule that out, other than that, I would look into replacing injectors, and maybe your o2 sensor.

 

Possibly bad TPS but i agree with 9d2TSi,get a multimeter or better an Auto Xray and start monitoring/checking different sensors.Definatly sounds like an electrical/sensor problem.Could even be a bad crank sensor.Who knows unless you can check it with some sort of metering device.

 

it could be a sensor, but do u have a BOV?? check if you do check and make sure the valve isnt bent or getting stuck.

 

as for the Subaru techs, they are all people that i went to high school with and have the intelligence of a chimp. i graduated in 01.

it has 67,xxx miles on it. i do maintain it religiously. i am on the 4th set of plugs, my filter is washed every 3 months(k&n), i change the oil every 5,000 miles(manual says 7,500)with Mobile1 synthetic or royal purple.

where do i find the specs on the mas output? i have every piece of test equipment you could think of(dad builds 6 and 7 second drag cars).

i do have a bov and i have put the stock one back on, and it did not fix it . i also have an up, tbe, snorkel removed.

but on a good note the car gets 27-29 mpg when it does this.

the worst part is i will go 3-4 months without a problem, and as soon as i go out of town it does this. then within a week of getting home it runs fine again. yesterday and today it is running great.i finaly put a fresh tank of gas in it late last night and it was running good before the refill. so i don't believe it is bad gas.

 

Backfires or pops from exhaust?

Running any differently? Im def thinking something with the fuel delievery.

Have you taken out the injectors? Get them checked "Flow test" and compare to stock specs.

Getting normal gas mileage and all....hmm

 

You clean the filter every 3 months? Everything you're saying points me straight to the maf. There's more than likely K&N oil all over it, messing up it's readings.

I looked for how to test the maf itself and really couldn't come up with anything, it basically said to replace it. But, I did come up with a list of things for you to check or have checked. The FSM is kind of vague when it comes to this stuff. That, or I'm too dumb to properly use it. This isn't an exhaustive list, but these parts were most common in all of the areas of rough idling, running, stalling, etc, etc...

Idle air control solenoid
Pressure sensor
Mass air flow and intake temp sensor
Ignition parts
Engine coolant temp sensor
Crank position sensor
Cam position sensor
Fuel injection parts

 

You clean the filter every 3 months? Everything you're saying points me straight to the maf. There's more than likely K&N oil all over it, messing up it's readings.

I'll look for some specs for you.

good point I had this happen to a bike of mine. The oil eventually was to much for into the carb "OR THE MAF" on the wrx. But...it does cauz bogging

 

i had the same problem with my yz 490 and 660 raptor. i only lightly oil it that is why i clean it every 3 months( change of season). i have checked the mas multiple times and it is alway clean and dry.

As for now the car is running fine and i am now back to 19-21 mpg which is normal in my everyday commute. and i bet it won't do it again until i go out of town next.

could it be something in the gas in my area that my car likes? i live 40 miles north of DC.
it will only do this when i am on my way home from out of town, and lasts 3-4 days when home. then runs fine.

i drove to California 2 years ago and it ran fine on the way there and for 3 weeks ran great on 91 octane. before hitting Nevada it started this up for a week and a half it did this. i got home and 3 days later changed the plugs(which required disconnecting the battery),oil,and rotated the tires. then it ran fine.

i really think that it is in the electronics.

 

Did you ever try to resistor for the EGT? I didn't see anywhere on the post that you've tried that. The last thing you said was you were going to pick one up but that's about it.