I bought a 2004 Forester about six months ago. Automatic transmission;turbo.

 

I use this mostly to run around town; no problems. But when I take it on the highway I periodically experience a momentary loss of power and accleration. The RPMs drop way down and the check engine light flashes on. Then the car recovers and performs normally. For a little while.

 

It usually happens after the car is warm. It will happen five or six times in the course of a 25-30 mile trip.

 

Has anyone else expereinced this or can anyone make a suggestion of what's happening? My service guys tell me they can't find anything wrong with the car.

 

I'm stumped.

My service guys tell me they can't find anything wrong with the car.

BS

If engine light was on, the code is stored in ECU memory. A good OBD2 interface software will show you "freeze" engine conditions when the faults occured. Probably problem with sensor connection, many sensors to check, get the code first.

if you want to read the code and you are local.

I'd bet that it's the turbo wiring. Turbos add complications to an already complicated engine system.

I had the same experience, BUT on a 2002 Forester Non-Turbo. After 5-10 minutes warmup, I could be on the highway, or in town, the engine would just SHUT OFF. No Chk eng light. It was under warrenty and the dealer had NO STORED CODES. It wasn't until I took the Service Rep for a ride that they started to do real Problem Determination.

 

All the time, I was told it was 'bad gas'. But I could reproduce it at some regularity. Turned out to be a defective FRONT Oxygen Sensor. Seems it was telling the ECU that the engine was running rich and shut off the injectors. So the ECU thought all was normal.

I finally found it, after the dealer replace a slew of parts, by unplugging the Oxygen Sensor. YES it set a code, YES the Chk Eng light was on, but then I could not get the engine to act up again. ( here the engine runs in 'OPEN' Mode)

By this time, The service Dept was sick of me and I think changed the sensor to please me. Outcome....All Fixed.

Afterward a guy I worked with 3 weeks later told me about a similiar failure he had on his 2003 Outback. His failure was more severe. When his car stopped, it just Died.....No restart. ECU....Sensors..injectors..Fuel pump...relays later found it to be the Oxygen Sensor.

I AM aware the Turbocharged engines.....ECU's....and sensors ARE different with different programming and parameters, but if you CAN reproduce it as I could, IT may be something to try.

My $.02....

I'm taking my vehicle back in for service tomorrow. Has anyone else had a similar expereince? Or anything to add?

 

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I use this mostly to run around town; no problems. But when I take it on the highway I periodically experience a momentary loss of power and accleration. The RPMs drop way down and the check engine light flashes on. Then the car recovers and performs normally. For a little while.

 

It usually happens after the car is warm. It will happen five or six times in the course of a 25-30 mile trip.

 

Has anyone else expereinced this or can anyone make a suggestion of what's happening? My service guys tell me they can't find anything wrong with the car.

 

I'm stumped.