2005 Outback Acceleration problem between 1500 and 2500 RPM

[elmccabe]

We have a 2005 Outback Turbo.  About 6 months ago we noticed (immediately) that we were having acceleration issues between 1500 and 2500 RPMs.   The car runs fine once you get over 2,500 RPMs but can be a complete dog between there.  We have taken it to 5 shops.  First shop said they don't know turbo engines enough, so sent us somewhere else.  Second shop said it was a problem with our catalytic converter and replaced it. Then said we needed a new engine, so we took it to our local shop that just works on Subarus. They were great but said there were no specific problems, turbo looked good, engine looked good, no spark plug issues.  They thought it was a transmission issue.  We took it to our transmission specialist who said there was no problem with the transmission. Finally took it to our local Subaru dealer who said there was no fuel filter on the car (not sure which previous fools took it off). They put a new one on and said there was nothing else wrong with the car.  I've been driving it and it works 80% of the time, but still has problems - occasionally - between 1500 and 2500 RPM.  Driving it in manual/sport mode seems to help - sometimes.

 

Any help would be greatly appreciated. 

[1 Lucky Texan]

any codes stored?

 

you may need to find a performance shop with a dyno or try to get some live data during a failure.

 

boost, AVCS issues would be suspect I think.

[elmccabe]

no codes - all shops checked that.  the 4th place we took it to was a performance shop.  No CEL either

[mikaleda]

2005 should be DBW maybe an issue with gas pedal? Just guessing though

[elmccabe]

Could it be a bad TPS?  If so, how do I test that?

[1 Lucky Texan]

live data. Get a laptop and tactrix cable and you can log boost, avcs percent, throttle position, etc.

 

there MAY be a way to get a similar set of data with an elm327 BT adapter and a smartphone.

 

 

here's an older video of the process;

Edited January 6, 2016 by 1 Lucky Texan

[mikaleda]

quote name="elmccabe" post="1313911" timestamp="1452099696"]

Could it be a bad TPS? If so, how do I test that?

If it is DBW there is a TPS, two gas pedal Sensors and a throttle motor that all have to work together. There is a long trouble shooting process to Go through to make sure everything is communicating properly and that there is no physical carbon blocking the throttle or making it stick. Watching the live data on a scanner while someone else drives it while its messing up should give you an idea of what isn't cimunicating properly. Might take a trained eye to see it though.