04 H6 3.0 outback intermittent jerking

[mikem]

04 H6 3.0 outback purchased 03/04 from dealer. In 7/04, 6700 miles, I took it to the dealer because it felt like the car was missing badly or the fuel injection was cutting out. At first I thought the A/C compressor the cause of the skip or hesitation. Felt like the compressor was way too big for the motor. Did a test with the A/C "Off" and the jerking continued. Not real bad but definetly a hesitation or misfire type of sensation. Not something you want to feel in a new car. Dealer "could not duplicate". Mecanhic told me he ran "the piss out of it to reset the transmission". Boy, was I impressed. Especially since during the test drive he related having been arrested over the weekend for "wreckless driving".

Today I experienced the same sensations at highway speeds and went thru the same routine of turning off the A/C. Skipping got worse and when I got to some congested traffic the transmission shifted down rather abruptly at about 5-10 mph. No big metal sounds, just a "thunk". Did the same thing shifting up at about the same speed. Finally got so bad I pulled off the road and figured I had maybe 10 miles of life left in the car. Shut it off, made a few calls looking for dealers and then headed to the nearest one, about thirty miles away.

Ran great. No hesitation, no shifting woes. Nothing but a new car running like it should. Drove it down the interstate at 75+ and it was charming to drive. Mileage is stable in mid twenties, no other symptoms.

What the heck is going on? Any guess, knowledgeable or otherwise, is appreciated.

Dealer got it this morn. No codes found. What is unmonitored that would cause this type of problem.? How can it misfire and not be captured by comp.? What would clear up with just swithching off the key for 15 mins.?

[Log1call]

Hi,

the trouble codes are mainly just for the sensors and the units the computer control, there is no code for the computer itself or for power or earth problems. Fuel problems won't show a code directly.

Faulty connections on wiring or faulty components in the computer can all be intermittently caused be heat, switching off for as little as ten seconds can sometimes be enough for them to cool down and restart. If it's a new vehicle just take it back and tell them to fix it.

[Cougar]

You could start by looking at the ignition area first. Make sure all the plug wires are snug. Look for other loose connections.

[mikem]

Drove the car again on a four hundred mile trip and the problems did not show up until 150 miles. Stopped into the dealer in Raliegh and they knew immediately what the problem was, a throttle positon sensor. Said they have replaced 6 already and they are not generating codes or CELs.The car started a new trick on the last trip. It would hold the current speed, be it 65 or 45, didn't matter, when you took your foot off the accelerator. Put it in nuetral and it would maintain the last rpm. Kinda tough to stop unless you take it out of gear. I will post this on the NHTSB site.

Drove it early this morn and the CEL is out and it runs like a top, except it runs after you take your foot off the gas.

Got it back to Greensboro dealer this morn and they called saying they had put in a new TPS. Don't know if any codes were recovered yet. Will post results.

Thanks for the input.

11/2/04 Got the car back this pm. New Throttle position sensor installed. No codes, no CEL tripped before installation. Dealer consulted with Southerstates Subaru in Raliegh and based on their advice the TPS was changed. Quincy at the Raliegh dealer is very sharp. Was told there is a Tech bulletin out now for this problem. I posted my experience on NHTSA complaint board due to sticking accelerator.

thanks for the comments.

[Cougar]

Keep us posted Mikem. Thanks for the update.