Subaru Outback hesitation HELP!!!!

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drtrost1
Posts: 4
Joined: Sat Nov 21, 2015 6:48 pm

Subaru Outback hesitation HELP!!!!

Unread post by drtrost1 » Sat Nov 21, 2015 7:01 pm

Have a 2006 Subaru Outback 2.5i SOHC auto trans with 188K miles.

Since I changed my AC, alternator, steering pump belts, have noticed intermittent hesitation with acceleration - particularly around 2500 RPM and particularly around 25 mph and 60-65 mph. No CEL's whatsover.

Have done a ton of internet trolling about this problem and done the following:

Got a plug in scan tool that suggests lean condition when accelerating only - not lean at idle (although idle is a little rough too)
Sprayed carb cleaner for vacuum leaks
Replaced my spark plug wires (with 188K on them!) and spark plugs
Replaced my fuel pump
Did dry compression tests on 4 cylinders - all within 15% of one another
Replaced downstream O2 sensor (no CEL but scan tool suggested it was a little lazy in terms of voltage)
Cleaned MAF sensor
Cleaned EGR valve
Added several fuel injector cleaners to tank - Techron was the only one that seemed to help
Checked fuel injector resistances
(Most recently) pulled old fuel injectors and replaced with cheap aftermarket ones while I send stock ones for cleaning/testing

Only thing that seemed to help was Techron, but replacing the fuel injectors (admittedly with cheap ones) hasnt made any difference.

Any ideas?

Unfortunately, the throttle body sensor on this car is part of the electronic throttle system (drive by wire) and is not supposed to be removed/tested/serviced separately. i have thought about replacing the throttle relay, but am out of ideas.

Any thoughts would be greatly appreciated,

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carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: Subaru Outback hesitation HELP!!!!

Unread post by carriedi » Sat Nov 21, 2015 11:09 pm

Subaru has a tsb that has this in it: http://m.oemdtc.com/Subaru/TechTIPS/201 ... chTIPS.pdf

"How much is too much? What can happen if you put too much oil in an engine? If you’ve ever seen
an engine that had way too much oil added, you’d say a lot can happen and all of it is very bad and
expensive. What if it’s just a little over full, say by half a quart? Shouldn’t hurt anything...right?
Excess will just burn off...right? Wrong. What if we told you an engine just half a quart over full could
result in a drivability concern? It can.
If you encounter a concern of sluggish operation, hesitation, or surging on a vehicle, you may want
to check the engine oil level when the engine is cold. If the engine oil is over-full, drain the excess
oil and see if the condition is corrected. Conditions like this will generally be most noticeable when
accelerating up a grade. If you are monitoring the ECM using the SSMIII, you may notice knocking
correction occurring at the same time you experience the surging sensation. We are aware of
concerns like this occurring in the field following both dealer and aftermarket oil changes. Always
confirm the engine oil level is correct following any service. What if the car is new? What if the
mileage isn’t near the service interval? Don’t discount the possibility of someone adding oil to an
engine between services. After all, if it’s down half a quart why not just add the whole quart. It’s
only a little over full. What could it hurt? Now you know. It could hurt drivability"

this may not be you problem but it is something to check.

you may need to drive with a scanner graphing the fuel trims and looking at the o2 sensors when the problem is happening.
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drtrost1
Posts: 4
Joined: Sat Nov 21, 2015 6:48 pm

Re: Subaru Outback hesitation HELP!!!!

Unread post by drtrost1 » Sun Nov 22, 2015 7:53 am

Thanks - I will check this.

drtrost1
Posts: 4
Joined: Sat Nov 21, 2015 6:48 pm

Re: Subaru Outback hesitation HELP!!!!

Unread post by drtrost1 » Sun Nov 22, 2015 10:22 am

So I checked my oil on cold engine on level ground this morning - dipstick was bone dry - added about 2 quarts of oil which got the level to low. i get my oil changed every 5000k - usually about a quart low each oil change - havent noticed any puddles under car whatsoever - any ideas? I imagine the low oil and hesitation are probably related,

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carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: Subaru Outback hesitation HELP!!!!

Unread post by carriedi » Sun Nov 22, 2015 6:21 pm

the low oil level may or may not be a reason for the hesitation. you'll have to let me know about that when you drive it with the oil level at the correct level and see if the hesitation is gone or not. Oil usage or leaks on subarus is not uncommon. Valve cover gaskets, head gaskets, seal commonly leak. Aged motors will burn oil... You should check the oil at least once every month but hardly anyone does. I know I am a little slack in checking my fluid levels in a timely matter. I just take it for granted... until a light comes on or something. That's why many newer cars and trucks have level indicators on important fluids nowadays. Oil level, brake fluid level and coolant level have warning lights that come on in many vehicles today.

back in the 50's and 60's gas stations would check your fluid levels when ever you filled up for gas. That's back when gas was 20+ cents a gallon and people would fill up so you would be stopped for a while during the fill up. Now, you either fill it up yourself or some gas attendant fills the gas that doesn't even know where you dipstick is. So, it doesn't get checked anymore.

so, get it to the full mark and see how many miles it takes to use or loose a quart.
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drtrost1
Posts: 4
Joined: Sat Nov 21, 2015 6:48 pm

Re: Subaru Outback hesitation HELP!!!!

Unread post by drtrost1 » Sun Nov 22, 2015 6:39 pm

Thanks - I had what I thought was a low oil problem about a year ago (where I was more diligent about checking) that would always trigger a CEL - was told eventually that it was a leaky oil pan plug and was repaired (by Jiffy Lube - whom I dont trust to repair anything) and the low oil problem seemingly went away - now I am thinking the absence of a CEL lulled me into thinking the problem was fixed.

Had my head gasket replaced at 150k for an oil leak, too. Though about doing the valve cover gaskets (which dont look particularly oily, although I realize this can be deceiving) but due to clearance issues with the Subaru, I'd have to jack up my motor which I am not thrilled about doing. After a day of driving, it seems the hesitation was not immediately gone with oil fill but the last two drives today seem a little better. We will see. i've done just about everything I can to eliminate the problem short of replacing the throttle body, the A/F sensor, and the ignition coil - not to mention other thngs like the MAP sensor, camshaft position sensor, etc.

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