Please Help: Another Stuttering Problem

xxej20xx · 11-06-2009, 03:26 AM

I have a 2002 wrx with about 95k miles on the ticker. I bought the car about a year ago and it had a problem where it would stutter at about 4500 rpms, more or less. It will not go past 4500 rpms. It just keeps making a da da da da da da da da sound. Its completely stock with only a cobb uppipe. At 1/2 throttle it may get to about 6000rpm in nuetral, but wot just fails at 4500 rpms no matter how long I hold it. The car used to have this problem and I put a different bov and a short ram intake. This solved the problem and the car ran fine until a cracked piston 3 months down the line. The engine was just rebuilt, and with the rebuild the problem returned. I pulled a tgv stuck shut code but just cleared it and got new tgvs. I also have a heater sensor circuit code as the hole is plugged due to the uppipe. The only other thing I may add is I don't know what the guy who had the car before me did to the car as far as tune, but then again I don't know how an intake and bov remedied the problem before. Maybe the car is tuned stage 2 or something? Also the car is looking to run about 14 to 15 psi. Idk if that helps. Any help would be greatly appreciated.

-Thank you in advance
Eric

blakkboxer · 11-06-2009, 12:17 PM

http://forums.nasioc.com/forums/showthread.php?t=781242

xxej20xx · 11-06-2009, 01:29 PM

Thanks for the link. But I don't see how cleaning my IAC would help me. The car has a healthy idle, and it seems the IAC only adresses idle problems....

xxej20xx · 11-06-2009, 04:40 PM

Come on. Nobody knows? I'm sure there's a lot of gurus and specialists out there who can chime in on this. Also may post a video later.

spinningcain · 11-06-2009, 07:38 PM

Could be the Tune How much boost are you hitting when it cuts out? You could be hitting the boost cut. Give the maf a good cleaning and reset

xxej20xx · 11-06-2009, 07:45 PM

Here's a video of the problem

YouTube- video-2009-11-06-13-56-25

xxej20xx · 11-06-2009, 07:54 PM

YouTube- Subaru hesitation

xxej20xx · 11-06-2009, 07:57 PM

Quote:

Originally Posted by spinningcain

Could be the Tune How much boost are you hitting when it cuts out? You could be hitting the boost cut. Give the maf a good cleaning and reset

I have cleaned the maf before but will clean again for good measure. I am getting boost for 10 psi in first. To around 14 in second. Maybe a bad boost solenoid? Should I put on my manual boost controller and go from there?

tpendergraft85 · 11-06-2009, 07:58 PM

spark plugs?

xxej20xx · 11-06-2009, 08:07 PM

Quote:

Originally Posted by tpendergraft85

spark plugs?

Maybe. Ill swap those out when I do my oil change today. But I'm running the same plugs I did when my car was running normal. ????

fastwrx25 · 11-06-2009, 09:42 PM

spark plugs +12345

I had the same prob, stuttering ~4k+ rpm in boost. Turned out to be the plugs since I was long overdue in replacing them.

changing plugs isn't that hard at all took me around less than 1 hr first time doing it. Don't overtorque them.

plugs are a wear item. read the spark plug faq to figure out what brand, type to use. Use NGK

could also be fuel filter also.

how good have you been with maintaining the car? follow the maintenance schedule to avoid probs like this. Also have you been throwing and misfire CELs?

02blueru · 11-07-2009, 12:29 AM

Could also be a fueling issue. I had the same problem and turned out to be a bad fuel pump.

xxej20xx · 11-07-2009, 03:05 AM

I don't know if this helps but when the cars nearly empty. The car pulls like a bat out of hell. So I'm thinking bad tune? When the cars out of gas it leans enough to run right?

Quote:

Originally Posted by 02blueru

Could also be a fueling issue. I had the same problem and turned out to be a bad fuel pump.

xxej20xx · 11-07-2009, 02:25 PM

Bumppp.....any more suggestions?

metric · 11-07-2009, 08:47 PM

sounds to me theres a timing issue,set the crank on tdc and make sure all the cams are timed correctly. also,verify the tgv's are staying open and not opening and slamming shut on a run,which could be the case.

Haelan · 11-07-2009, 08:49 PM

A faulty crank position sensor has been known to cause hesitation on or after 4.5k rpm. You may want to swap with a known good sensor and see if it clears up. It's very simple to change out.

soob noob · 11-07-2009, 09:17 PM

i changed my plugs and cleaned my maf with the maf cleaner from autozone and my stutter went away

blakkboxer · 11-08-2009, 12:48 AM

Quote:

Originally Posted by soob noob

i changed my plugs and cleaned my maf with the maf cleaner from autozone and my stutter went away

glad to hear problem solved, cheers!

xxej20xx · 11-20-2009, 08:02 PM

Bummmppp any more suggestions?

paintbing · 11-20-2009, 08:43 PM

^ I'll suggest some more ideas when you post what you've done to try and fix it. - j/k

Did it JUST start to happen, or has it been a problem that slowly came and went and progressively got worse? DId you make any changes lately that caused it to start?

It LOOKS like a fuel cut issue (Kind of like 02blu said above). It could be a clogged FUEL FILTER so at higher boost (Higher fuel demand) the failing pump OR clogged filter is restricting the flow of fuel... Just some thoughts.

xxej20xx · 11-20-2009, 10:08 PM

I've always had ths problem. Then it went away. Rebuilt engine. Same problem came back. So it must be a sensor or something that went bad then got knocked around and started to work again? Maybe? The first time the problem fixed when I hooked up a sri. Maybe it moved the maf around just enough? Could it be a bad maf? And how would I tell?

Quote:

Originally Posted by paintbing

^ I'll suggest some more ideas when you post what you've done to try and fix it. - j/k

Did it JUST start to happen, or has it been a problem that slowly came and went and progressively got worse? DId you make any changes lately that caused it to start?

It LOOKS like a fuel cut issue (Kind of like 02blu said above). It could be a clogged FUEL FILTER so at higher boost (Higher fuel demand) the failing pump OR clogged filter is restricting the flow of fuel... Just some thoughts.

11-06-2009, 03:26 AM	#1
xxej20xx Scooby Newbie Member#: 192918 Join Date: Oct 2008 Chapter/Region: SCIC Location: corona, CA Vehicle: 2002 wrx platinum silver	Please Help: Another Stuttering Problem I have a 2002 wrx with about 95k miles on the ticker. I bought the car about a year ago and it had a problem where it would stutter at about 4500 rpms, more or less. It will not go past 4500 rpms. It just keeps making a da da da da da da da da sound. Its completely stock with only a cobb uppipe. At 1/2 throttle it may get to about 6000rpm in nuetral, but wot just fails at 4500 rpms no matter how long I hold it. The car used to have this problem and I put a different bov and a short ram intake. This solved the problem and the car ran fine until a cracked piston 3 months down the line. The engine was just rebuilt, and with the rebuild the problem returned. I pulled a tgv stuck shut code but just cleared it and got new tgvs. I also have a heater sensor circuit code as the hole is plugged due to the uppipe. The only other thing I may add is I don't know what the guy who had the car before me did to the car as far as tune, but then again I don't know how an intake and bov remedied the problem before. Maybe the car is tuned stage 2 or something? Also the car is looking to run about 14 to 15 psi. Idk if that helps. Any help would be greatly appreciated. -Thank you in advance Eric

11-06-2009, 01:29 PM	#3
xxej20xx Scooby Newbie Member#: 192918 Join Date: Oct 2008 Chapter/Region: SCIC Location: corona, CA Vehicle: 2002 wrx platinum silver	^^^^^ Thanks for the link. But I don't see how cleaning my IAC would help me. The car has a healthy idle, and it seems the IAC only adresses idle problems....

11-06-2009, 04:40 PM	#4
xxej20xx Scooby Newbie Member#: 192918 Join Date: Oct 2008 Chapter/Region: SCIC Location: corona, CA Vehicle: 2002 wrx platinum silver	Um help Come on. Nobody knows? I'm sure there's a lot of gurus and specialists out there who can chime in on this. Also may post a video later.

11-07-2009, 02:25 PM	#14
xxej20xx Scooby Newbie Member#: 192918 Join Date: Oct 2008 Chapter/Region: SCIC Location: corona, CA Vehicle: 2002 wrx platinum silver	bump Bumppp.....any more suggestions?

11-07-2009, 08:47 PM	#15
metric Scooby Newbie Member#: 216064 Join Date: Jul 2009 Location: frederick,md Vehicle: 02 wrx wrb	sounds to me theres a timing issue,set the crank on tdc and make sure all the cams are timed correctly. also,verify the tgv's are staying open and not opening and slamming shut on a run,which could be the case. Last edited by metric; 11-07-2009 at 08:50 PM. Reason: hmmm

11-06-2009, 12:17 PM	#2
blakkboxer Scooby Specialist Member#: 167244 Join Date: Dec 2007 Chapter/Region: TXIC Location: Dall'ass Vehicle: 03 WRX MBP almost18g'd CFC#029!	http://forums.nasioc.com/forums/showthread.php?t=781242

11-06-2009, 07:38 PM	#5
spinningcain Scooby Specialist Member#: 176490 Join Date: Apr 2008 Chapter/Region: SWIC Location: Las Vegas Vehicle: 2004 WRX VF39 silver	Could be the Tune How much boost are you hitting when it cuts out? You could be hitting the boost cut. Give the maf a good cleaning and reset

11-06-2009, 07:58 PM	#9
tpendergraft85 Scooby Newbie Member#: 83198 Join Date: Mar 2005 Chapter/Region: MWSOC Location: Wichita, KS Vehicle: 2002 WRX Wagon WRB	spark plugs?

11-06-2009, 09:42 PM	#11
fastwrx25 Scooby Specialist Member#: 126441 Join Date: Sep 2006 Chapter/Region: SCIC Location: california Vehicle: 02 bugeye	spark plugs +12345 I had the same prob, stuttering ~4k+ rpm in boost. Turned out to be the plugs since I was long overdue in replacing them. changing plugs isn't that hard at all took me around less than 1 hr first time doing it. Don't overtorque them. plugs are a wear item. read the spark plug faq to figure out what brand, type to use. Use NGK could also be fuel filter also. how good have you been with maintaining the car? follow the maintenance schedule to avoid probs like this. Also have you been throwing and misfire CELs?

11-07-2009, 12:29 AM	#12
02blueru Scooby Newbie Member#: 80012 Join Date: Jan 2005 Chapter/Region: RMIC Location: Salt Lake City, UTAH Vehicle: 02 WRB Bugeye Ducati Monster 620 Dark	Could also be a fueling issue. I had the same problem and turned out to be a bad fuel pump.

11-07-2009, 08:49 PM	#16
Haelan Scooby Specialist Member#: 151045 Join Date: Jun 2007 Location: NW Indiana Vehicle: 2004 JBP WRX Stage II - Monster TD04	A faulty crank position sensor has been known to cause hesitation on or after 4.5k rpm. You may want to swap with a known good sensor and see if it clears up. It's very simple to change out.

11-07-2009, 09:17 PM	#17
soob noob Scooby Newbie Member#: 220158 Join Date: Aug 2009 Chapter/Region: RMIC Location: santaquin/orem Vehicle: 02 bugeye murdered out	i changed my plugs and cleaned my maf with the maf cleaner from autozone and my stutter went away

11-20-2009, 08:02 PM	#19
xxej20xx Scooby Newbie Member#: 192918 Join Date: Oct 2008 Chapter/Region: SCIC Location: corona, CA Vehicle: 2002 wrx platinum silver	Bummmppp any more suggestions?

11-20-2009, 08:43 PM	#20
paintbing Scooby Specialist Member#: 59388 Join Date: Apr 2004 Chapter/Region: RMIC Location: Utah --> San Luis Obispo, CA Vehicle: 2003 WRX - Hybrid I do my own stunts	^ I'll suggest some more ideas when you post what you've done to try and fix it. - j/k Did it JUST start to happen, or has it been a problem that slowly came and went and progressively got worse? DId you make any changes lately that caused it to start? It LOOKS like a fuel cut issue (Kind of like 02blu said above). It could be a clogged FUEL FILTER so at higher boost (Higher fuel demand) the failing pump OR clogged filter is restricting the flow of fuel... Just some thoughts.

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