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Old 05-15-2001, 08:23 PM   #1
IMPREZAmike
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move bi*ch get out da way

Question Interesting hesitation problem - Troubleshooters UNITE!

Here's my current set-up
MY98 2.2L OBS
Minnam Intake w/ GReedy Airnix
Stromung Single tip
removed intake silencer.

OK, so if im crusing around and the car drops below 2K RPMs and i step on the gas, the car hesitates/shudders as if it is out of gas. It is real annoying and I cant figure it out. I just had the 60K mile tune-up yesterday (replace plugs, fuel filter, fluids etc etc) and it stil happened, although not as bad. Could this be a clogged fuel line? If so how do i unclog it? The dealer said it could be the MAS failing because of the intake but they would need more time for trouble shooting. Any ideas would be greatlly appreciated. Thanks!

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Old 05-15-2001, 09:30 PM   #2
North Ursalia
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<FONT face="Comic Sans MS">Well, I would hope the fuel lines wouldn't be clogged per se, as the fuel filter is the biggest restriction in the equation and is designed to stop the crud. Perhaps, especially because it's a low RPM issue, the O2 sensors are suspect. A failing O2 sensor would give you lots of bog at low rpm that would start to diappear the more the throttle opened up for you and the rev's climbed...

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Old 05-16-2001, 12:19 AM   #3
MichiganRS
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Fuel pump
o2
Plug wires

but being a 98 most likly what the dealer said run some fuel cleaner to
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Old 05-16-2001, 05:16 AM   #4
pottsie350
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How long has it done this? I'd say it's not the fuel system if it runs ok at higher rpms.
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Old 05-16-2001, 06:08 AM   #5
IMPREZAmike
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It has been hapening for about 3 weeks now. I guess i'll have them check the o2 sensor. next time in in......it has decreased since i got the new plugs/fuel filter...maybe it is just working itself out.

thanks guys

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Old 05-16-2001, 06:30 AM   #6
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Wasn't there a recall on some of those O2 sensors?
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Old 05-16-2001, 10:53 AM   #7
North Ursalia
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<FONT face="Comic Sans MS">Yes, but only on the 00 model Impreza's and Foresters (maybe some 01's too).

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Old 05-16-2001, 11:35 AM   #8
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do a search back a ways and you;ll find a guy up in Canada had/has the same problem....I dont know if or how he resolved it. Have you changed your plugs yet? Try a few tanks of fuel system cleaner and a new fuel filter after that. Also check your ignition coil pack, wires and plug connections to make sure there is no rust or anything suspect there....
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Old 05-16-2001, 03:42 PM   #9
altibaby
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Same problem for me...
I did replace my O2 sensor under recall(also change to NGK Platinum plugs) but the problem is still there.
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Old 05-16-2001, 03:50 PM   #10
Eric Gagnon
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mine did it too last week.. but i reset the ecu and it seems better now. not sure for how long though...

Eric
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Old 05-17-2001, 01:35 PM   #11
Kevin Thomas
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I just had the same EXACT problem this week. I changed my spark plugs and it helped but the problem was still there. It was very noticable between 1800-2500rpm. Light throttle and the engine would bog then pick up once it got past 2600rpm or so. It was really annoying.

I had a brand new O2 sensor that I put in a week ago. I didn't think it had anything to do with my car bogging but it did. The dealer found out that something was wrong with my O2 sensor harness and something needed to be 'extended'. I do not know the details but that was definitely the problem. Riding around town before the fix, my O2 sensor would read lean until I was above 3k rpmsa and then it would go back and forth to lean and rich. After the O2 sensor fix, all of my low end torque is back and my O2 sensor fluctuates back and forth at idle and low speed driving.

So have your O2 sensor checked. I'm almost positive it's the source of your problems since what you described is exactly the same problem I had up until this Tuesday. Good luck!

[This message has been edited by Kevin Thomas (edited May 17, 2001).]
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Old 05-17-2001, 01:54 PM   #12
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You have a MAS/MAF and nothing correcting the air/fuel ratio because of the intake. Sounds almost like a WOT map you're running really rich (cauing bog) or lean (causing detontation/ECU retarding ignition).

Let me guess, it doesn't happen when you gradually put your foot to the floor, just when you romp on it?
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Old 05-17-2001, 03:25 PM   #13
IMPREZAmike
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8 - you nailed it! thats exactlly what happens..although i think the new spark plugs/fuel filter helped out because it didnt happen at all yesterday or today. I have an S-AFC but i havent put it in yet and that should help i assume?

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Old 01-08-2002, 10:22 AM   #14
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sorry to bring this back from the dead, but my GF is having a problem with her car that sounds exactly like this. My suspects are MAF & O2. I'm pretty sure its running rich, so fuel filter wouldn't do it. its been a while since this was posted. What finally fixed teh problem?

-IggDawg
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Old 01-08-2002, 11:48 AM   #15
RigdenZW
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Is there such a thing as too much air flow? I noticed that after I put on my ganzflow that if I stomped it, the engine sounded/felt like it took a big gulp of air.. missed a beat .. then revved like mad. It would last a millisecond (not really a stutter just a little air popping noise) but I don't remember it being there before the new intake. Doesn't happen when slowly giving it throttle.

Maybe I just couldn't 'hear' it before..
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Old 01-08-2002, 11:56 AM   #16
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Did you reset the ECU after you installed it? you might be running an obsolete air map.

-IggDawg
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Old 06-28-2005, 09:20 AM   #17
tbert
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This is a very old thread to bump, but I would like to see the resolution/outcome of O2 sensor replacement suggestion on this problem, as I am experiencing the same thing now. When I accelarate swiftly (not WOT) in lower rpms, I get the bogging. My car behaves exactly like Mike's car...

If this problem is resolved by replacing the O2 sensor, is this an easy replacement, or do I have to have the dealer do it? Where is it located? Bunch of n00b questions I have today....Oh, and my car is a completely stock 2000 OBS with 48K on the odo.

I appreciate your help in advance.

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Old 06-28-2005, 09:23 AM   #18
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Quote:
Originally Posted by 8Complex
You have a MAS/MAF and nothing correcting the air/fuel ratio because of the intake. Sounds almost like a WOT map you're running really rich (cauing bog) or lean (causing detontation/ECU retarding ignition).

Let me guess, it doesn't happen when you gradually put your foot to the floor, just when you romp on it?
So what can one do to solve this problem? Reset the ECU? Replace the O2 sensor?

tbert
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Old 06-29-2005, 09:41 AM   #19
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bump for an answer!!!

Come on guys, don't make me ask teh OT. They scare me. aranoid:

-
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Old 06-29-2005, 11:51 AM   #20
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I've been experiencing a slight hesitation similar and I was leaning to my O2 sensors or MAP sensor.
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Old 06-29-2005, 12:07 PM   #21
John2.5RS
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I've been experiencing a slight hesitation similar and I was leaning to my O2 sensors or MAP sensor.
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Old 06-29-2005, 04:10 PM   #22
rob
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Use an ohmeter to check your coil. I have had 2 fail and found a failed one on my buddies '99RS

http://home.comcast.net/~r.files/sube_manuals/coil.jpg
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Old 06-29-2005, 07:12 PM   #23
Penphoe
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Hmm, interesting to see this thread pop up. I'm experiencing similar problems as well!

LaterZ!
Darren!!
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Old 07-02-2005, 02:42 AM   #24
Penphoe
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Well, I just reset my ECU while I was checking my plugs, wires and coils. It doesn't hesitate anymore!

I'll keep you informed on how long it stays away for.

LaterZ!
Darren!!
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Old 07-02-2005, 07:06 PM   #25
doomonu
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This seems like a common problem for people who have modified their intakes. I've been having the same problem ever since I took the intake silencer out. I'll go reset my ecu and see if that clears things up.
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