CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Subaru Engine (Lack Acceleration) and Cruise Control Problem

Need insight on Subaru (04 Forester XT) engine issue that occurred yesterday: car was running perfectly (weather was heavy snow, 30 degrees, icy); stopped to fill up for gas (premium); started engine and a few things happened:



1) check engine light turned on, 2) cruise control light started blinking, 3) once on highway, engine emitted rough, labored sounds only when accelerating, 4) car lacked power during acceleration, 5) cruise control did not work.



Shops are closed today - any ideas on what the problem could be? Thanks!!

The simplest thing I can think of is checking the gas cap to make sure it was properly installed when you filled up.

In addition to Craig’s valuable recommendation, I want to add another possibility as well as a question. First the possibility:

Is it possible that whoever filled your tank was one of those idiots who keeps forcing gas into the tank after the pump “clicks off” for the first time? If so, then it is very possible that your evaporative emissions system has been damaged by excess gas flowing into the carbon canister and thus, messing up your engine management system. Doing this once is not a problem, but repeated bouts of forcing extra gas into the tank takes its toll on the evaporative emissions system over time and that carbon canister is VERY expensive to replace. Hopefully, nobody has been abusing your car in this fashion.

And now the question:
Does your engine actually require premium gas? Unless the Owner’s Manual specifies premium gas, you derive NO benefits from using it, despite the old wives’ tales about premium gas “burning hotter”. (It doesn’t!) All you are doing by using premium if the engine does not require it is throwing money down the drain.

I could see most the problems happening if the new fuel was contaminated with water. I don’t see how that would effect the CC though. Check the owner’s maunal for an explination of the blinking light. It may shed some light to the trouble there.

The CC has failed due to the engine light. Under certain running conditions it simply disables itself until CEL is cleared.

Given all your symptoms I would take it in. The code(s) need to be read and then an idea of problem will come about.

Thanks so much for the help. We just checked the gas cap (all good there) and turned on the car again this AM - when in drive (with the brake on), it sounds like a chain going around a spoke or some sound of that nature (when standing outside the car, it seems louder near driver’s side/front wheel). When accelerating, it sounds like a wind tunnel, with the volume on the high end at first acceleration. Craig, boy do I hope it’s not the evap emissions system!

VDCDriver: Yes, the owner’s manual calls for premium.

Take it IMMEDIATELY to a shop, dealer or independant. It could be benign, but sounds like something can get expensive quickly. Hurry!!!

There are a lot of rotating mechanicals inside the engine, and, if you cannot isolate the sound to something on the accessories external to the engine, internal noises like this can spell very expensive repairs.

I Agree, you need to have it looked at ASAP. I think filling the gas tank was coincidental if you are hearing mechanical noises.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

Regarding warning lights:

  1. if the coolant temp light comes on, shut off the engine ASAP

  2. if the oil warning light comes on, shut off the engine ASAP

  3. if a FLASHING MIL/CEL comes on, shut off the engine ASAP

    ASAP means driving to the berm of the highway right now and not waiting for the next exit.

But if the MIL/CEL is not flashing, then it’s not an urgent indicator.

The noises that you are hearing are not connected with the evaporative emissions system, so although that system may be problematic, I don’t see a connection with that noise, which sounds like it could potentially be expensive.

Personally, I would not advise running the engine, in order to minimize futher damage, and I would suggest that you have it flatbedded (NOT towed) to the dealership for diagnosis. I agree with Craig that the emergence of the noise and the filling of the tank are probably not connected.

Check the vacuum hose to the cruise control. It could have split, or fallen off. Plug the hose, toward the engine intake, and test drive.

This is all good stuff! Thanks for your help. We’ll see what the service guys say tomorrow.

You’re running in limp mode. Something failed. It could even be the computer if no solution is easily found or if the codes are nonsense.