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Old 05-09-2003, 08:42 AM   #1
Scooby Newbie
Member#: 16400
Join Date: Mar 2002
2002 Outback Sport
Savannah Green

Question hesitation problems

I have a 2002 OBS AT. For the past 3 days, if I start up my car and slowly start moving I get a noticeable hesitation where it feels like it is going to stall and then if I give it some more gas it speeds up fine. Once I've been driving for a couple of minutes it won't happen again no matter what I do to duplicate it. If I let the car sit for 4 maybe 5 hours and let it cool down or leave it overnight it will happen again but only when I first start it up. The only mod I have is PDM CAI and K&N filter which I put in several months ago. It may be a coincidence but my CAI doesn't quite sound the same lately, its not as loud at WOT. My car is driving fine otherwise. Anyone have this happen to them or have any ideas what it might be? I know it's under warranty and I can bring it to the dealer but I'd like to get an idea of what is first so I can decide whether or not to remove my CAI and bring it back to stock.

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Old 05-09-2003, 12:09 PM   #2
Scooby Specialist
Member#: 32846
Join Date: Feb 2003
Chapter/Region: MAIC
Location: Elkton, VA
1998 Impreza L-SOLD
Arcadia Green

Default Hesitation

Could be the IAC valve, Idler Air Control Valve. Usually somewhere near the intake manifold and are in different places on different models. There are so many other things that could contribute to a hesitation. Dirty Throttle Body, clogged PCV (it should rattle when you shake it and feel vacuum on it when running and out of valve cover), faulty injectors, as well as an assortment of ignition areas including the spark plugs. It only does it when you first start it up though, that kind of stumps me b/c it doesn't do it all the time.

Logical thought makes me want to think that maybe your intake filter isn't cleaning properly, maybe its loose b/c itís making a different sound. And maybe the throttle body got all gunked up b/c of this. I'm just trying to put two-and-two together, but I'll be the first to tell you, I'm not a mechanic. If you do take the car back to the dealer just make sure they are not going to be dickheads over you having a intake.

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Old 05-09-2003, 12:35 PM   #3
Andrew Bacon
Scooby Specialist
Member#: 2267
Join Date: Sep 2000
Chapter/Region: SCIC
Location: LA dentention core


I have a simular problem, but my 00' RS hesitates at low speeds, low RPM and heavy throttle. It does this intermittantly regardless of how long the engine has been running. It usually does it in 2nd, but has done it in 1st and 3rd too. Say I'm comming out of a turn in 2nd, I hit the throttle hard and it stumbles untill 2,500 RPM or so then picks up and runs fine to redline. A couple of lights later, it will do it again. I have been running a CAI for 30K miles and a header for 15K miles, but this problem just started about 5K miles ago. I cleaned out the PCV valve, checked my plugs and ignition wires, but I'm not sure where the IAC is.

Is it cool to spray TB (NOT carb & choke) cleaner in the TB to clean it? This is my first EFI car and I'm still learning after 53K miles!
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