Engine stalls while driving

Tiny
JOEYOLIVARES88
  • MEMBER
  • 2008 SUBARU IMPREZA
  • 2.0L
  • 4 CYL
  • AWD
  • MANUAL
I change my2008 2.0 subaru impreza's exhaust pipe and mufler, I used 2inches stainless pipe and a dual tip muffler from a 2.5 subaru impreza wrx sti's I just what to ask you after changing, why my car keeps on dying if I step on the gas and then let go, more often when the aircon is on. Its like the idle isn't enought, how do I fix it? Thanks!
Wednesday, June 4th, 2014 AT 8:44 AM

45 Replies

Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok so what all did you do? Just exhaust? Did you keep the O2 sensors? Did you have to unplug them and maybe forgot to plug them back in? Is the check engine light on? Get back to me with some answers and we will see what we can do ok.
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Wednesday, June 4th, 2014 AT 8:53 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
The sensors where never removed?We change the pipe after the sensors?So the sensors does not have a problem?The check engine light is not on?I thought maybe its the mufflers problem so I removed it and try again but the problem is still there thanks for helping me
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Wednesday, June 4th, 2014 AT 8:57 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
Sorry about the question marks I typed it wrong
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Wednesday, June 4th, 2014 AT 8:59 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok so you opened up the exhaust and now it is bigger so now it breaths differently. If I remember correctly this has a mass air flow meter. So if you would get some mass air flow cleaner and clean it, its cheap and a place to start. Did you do any air intake mods or any other mods? All the info I can get will let me better help you ok. Your welcome anytime
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Wednesday, June 4th, 2014 AT 9:08 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
Yes the car intake now is running on a racing filter from knn
whats the mass air flow meter?
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Wednesday, June 4th, 2014 AT 9:11 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
I included a pic below to help. If this gets dirty then it won't read the correct air coming into the intake and will cause running issues. Throttle response and idle and hesitation problems even. Let me know if there is improvement and we will go from there.
Image (Click to make bigger)
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Wednesday, June 4th, 2014 AT 9:18 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
O I get it is it the sensor on the air intake?When we convert it we also convert the sensor too, so now even its on racing filter mod the sensor is still on it
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Wednesday, June 4th, 2014 AT 9:24 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
How can I clean this properly?
Changing the exhaust has no problem?I think the factory exhaust pipe is 2-1/2 inches, is it ok to use 2 inches?
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Wednesday, June 4th, 2014 AT 9:26 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
When running the car has alot of power, the only problem is the poor idle, when I stop, or when I shift to neutral, the car would just die. And I have to restart it again
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Wednesday, June 4th, 2014 AT 9:29 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
That sensor can possible cause this that why I am asking to clean it. The exhaust should not have much effect on the problem you are having as long as the O2 sensors are in the correct spots and where not moved or modified. All you need to do is pull it out spray the wires with the cleaner and put it back. Let me know how it goes and we will take it from there ok.
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Wednesday, June 4th, 2014 AT 9:39 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
Ok thanks ill try it soon as sun raise, because its 12am here now, thanks I will email you tom!
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Wednesday, June 4th, 2014 AT 9:41 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
Hi
i cleaned the maf sensor today using electrical control cleaner
because I cant find the maf cleaner fluid?I even change the spark plug
to ngk iridium spark plug?But the problems still there then I try to start it again with out the knn air filter just for a while about 1 minute it gone worse
now the engine light is on the traction control light is on and the cruise light is always blinking?What should I do?
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Thursday, June 5th, 2014 AT 5:32 AM
Tiny
RACEFAN966
  • MECHANIC
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See if your local parts store does a free scan and scan it get the codes and get back to me with them and I will look them up and we will go from there ok.
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Thursday, June 5th, 2014 AT 7:50 AM
Tiny
JOEYOLIVARES88
  • MEMBER
  • 10 POSTS
Hi this morning when I start the car and driving?When you step on the gas hardly the rpm wont go up?It goes up very slowly when neutral it up very hard when driving?I went to a local store they told me that the throttle body should be cleaned after cleaning the idle problem is fixed but the engine lights are still on they hooked it up to there reading code device?The device can not read the code they used another one and still the same result?They unhook the battery for a long time to reset and connect the device again?The code still cannot be read or erased?The local store is the specialist of subaru cars they told me now that the problem of the car is the wirings now im waiting for the technitian to come?The dying problem is fixed but the other problem aquire?The rpm wont go up normaly it go up very slowly when just reving?If driving it goes up more slowly and hardly?And the code cannot be read by the device?What should I do now?
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Thursday, June 5th, 2014 AT 10:40 PM
Tiny
RACEFAN966
  • MECHANIC
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Check fuse 13 and fuse 4. Fuse 13 is in the underhood fuse box and is 7.5. Fuse 4 is in the fuse and relay box and is a 10 amp. These fuses go the to diagnostic connector and if either are blown the diagnostic connector won't read or may not power up.
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Saturday, June 7th, 2014 AT 6:35 AM
Tiny
TJQ5
  • MEMBER
  • 1 POST
  • 2007 SUBARU IMPREZA
  • 4 CYL
  • AWD
  • AUTOMATIC
  • 49,000 MILES
Hi my name is Travis and I am having a problem diagnosing a stall in my subaru and so is the dealership! When I accelerate from a dead stop and it switches gears to 2nd and gets between 20-30 mph., There is a short stall or bogg you can see the rpms stop and decrease instead of increasing like im letting my foot off the gas. Then it does the same thing in 3rd gear between 60-75 mph you can actually see the rpms decrease again for a longer time. Its as if the engine or tranny is straining. I asumed maybe fuel delivery error or electronic throttle body, maybe transmission, who knows because I sure dont! NOTE this happens in the same mph and rpm range everytime. If anyone knows what this is please let me know ASAP thanks and hopefully whatever it is its covered under warranty
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Monday, April 13th, 2020 AT 12:50 PM (Merged)
Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Have the dealer check the throttle by wire system.

There are three basic components in electronic throttle control that may be causing that problem.
* A position sensor on the accelerator pedal (actually there are 2 or 3 position sensors for redundancy).
* An electronically-controlled throttle body with a small electric motor to open/close the throttle (most use reduction gears to rotate the throttle shaft).
* A control module (the PCM or a separate ETC module that talks to the PCM via the CAN-bus or serial data link)


https://www.2carpros.com/forum/automotive_pictures/46384_throttlebywireschematic_1.jpg

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Monday, April 13th, 2020 AT 12:50 PM (Merged)
Tiny
LEMLEY73
  • MEMBER
  • 6 POSTS
  • 2002 SUBARU IMPREZA
  • 220,000 MILES
I replaced the spark plugs and knock sensor and it ran good for a week. Now it won't even make it up a hill. Keeps stalling.
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Monday, April 13th, 2020 AT 12:51 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Have the fuel pressure checked. It may be too low.

Is the check engine light on?

Roy
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Monday, April 13th, 2020 AT 12:51 PM (Merged)
Tiny
LEMLEY73
  • MEMBER
  • 6 POSTS
Yes check engine light goes on shortly after I get gas.
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Monday, April 13th, 2020 AT 12:51 PM (Merged)

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