My Outback, when warmed up and driving at highway speeds, starts to jerk. It doesn’t make a noise. If I take my foot off the accelerator, it stops. Sometimes it is frequent, sometimes hardly happens. Two different mechanics swore it was the spark plugs, fuel injectors, and wires. Two new sets did nothing. Then number two got a consult from someone who knows about Subarus. He said it needs some additive in the transmission fluid. That stopped the problem for a month or so. I went to a third mechanic, who thinks it is the torque converter freezing up. I also have some oil leaks, and went to get a second opinion on engine work. They are thinking it is the torque converter, too. So they took it to a transmission specialist. He says he didn’t get the code for the torque converter problem, although #3 mechanic did. He thinks it might be the fuel injectors! Help! Please!
I would first suspect the fuel pump causing the trouble. If you haven’t replaced the fuel filter yet then do that first, it may clear the trouble.
How many miles and what model year?
Assuming it is a newer model, check for any CEL’s and get any codes and post them back here (as a reply to your question)
I tend to believe it is the transmission, but don’t take my word for that. If “Transman” shows up, you can bet on anything he says about transmissions.
It would be really helpful if you would reveal the model year, odometer mileage, and engine type of your Outback. Details like that can make a difference when venturing a guess as to a diagnosis.
Thanks for the comments so far. My Subaru is a 1996 with a 2.5 L engine. It has 155K miles. The fuel pump is an interesting thought. I will watch for more ideas.
If it has been more than 30k miles since the fuel filter was replaced, then that needs to be done. If that does not help, then you should have your mechanic test the fuel pump’s output.
Thanks. I will tell the mechanic about the fuel filter. I think it is more like 50K since it was changed.
Interestingly, we have a dead 1999 Taurus, which was doing similar things, and was back and forth to the mechanic 4 times. We were heading there for the last time, having obtained some sort of vacuum hose (tiny piece), and it died on the road. When the mechanic (whom we had been telling we thought it was a transmission problem for months)saw it, he said the transmission was kaput. So we are suspicious about the Subaru’s problem.
If Transman is around and reads this, I hope he will give his thoughts.
Does the engine run steady, no changes in rpm or change in the sound of the engine?
Is the Check Engine light on?
iggy to transman, iggy to transman, we have an outback down, repeat, an outback down. sounds a lot like a donut problem, please leave the donut shop and respond, we have an outback down.
Before transman reads this, you can help him by giving the full maintenance history for the car’s transmission.
However, I will say that if the trans has not been serviced every 3 yrs/30k miles, then it is likely to be on its last legs–even if it is not causing the current problem. In other words, the trans fluid should have been changed 4 or 5 times since 1996. Has this been done?
The engine runs steady, and I haven’t noticed any change in rpm, except if I take my for off the gas pedal. There is no different sound in the engine either. The check Engine light is on, but it has been on for ages- if the gas cap isn’t tightened enough (3+ clicks) the light comes back on. Mechanics have reset it any number of times and say it is not the engine. However, the engine at this point is having leaking seals on the back wall, and we have been trying to find out if the transmission needs repair before doing that, as it will save about $500 not to have to drop the transmission separately, i.e. twice. I am very interested in your thoughts, Goldwing.
The problem you are having is most likely due to a weak fuel pump. The trouble you describe is a fairly common problem with Soobs due to a bad pump. It is way cheaper to replace a fuel pump than to work on the transmission. Even if it is just to eliminate the fuel pump as the trouble I think you would be wise to try that first and replace the filter before doing anything with the tranny.
That sounds good! If it is fairly common, I wonder why the mechanics haven’t thought of it. There are a lot of Subarus in the NC mountains where I live.
I don’t know why they haven’t brought up the fuel pump as a possible trouble. Replace the filter first naturally and if that doesn’t work, move on to the pump.