Last post on Aug 02, 2010 at 12:17 PM
You are in the Subaru Forester
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#1 of 23 Vehicle Speed Control/Surprise RPM Surge Issues
Mar 18, 2007 (5:22 pm)
I am contemplating buying a 2007 ForesterXT sports auto. I test drove the vehicle and like it. But I have read some disturbing things about a surging problem, at least in 2006 Foresters. According to the complaints I've seen, this sometimes seems to occur when the Forester (trimline unspecified) is traveling downhill. Another driver indicated that occurred when he/she took his/her foot off the accelerator before slowing down.
It appears that Subaru has attributed the problem to a drive by wire system. One person who posted something about this a year or so ago indicated that it affected "thousands" of Foresters.
Can anyone tell me more about this problem and what, if anything, Subaru has done/does to address it? I know several people who own Foresters and love them. But this kind of report gives me reservations about buying the vehicle. Thanks in advance.
#2 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [bkwaas]
Mar 18, 2007 (5:57 pm)
I have an '04 Forester XT w/ MT and have never had any surging. It was the first year for the drive by wire system back in '04. I don't recall seeing complaints on the Edmunds forums, but perhaps I just haven't been in the right forum.
#3 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [subearu]
Mar 18, 2007 (6:09 pm)
Thanks, Brian. I believe that the problem began in 2006, but I am not certain. There are several complaints about it on this site under "Subaru Forester Engine Issues". In particular, gman67's post titled "high idle".
There are also references to the problem on Google's "alt.autos.subaru" news group, under the posting "surging Forester".
#4 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [bkwaas]
Mar 18, 2007 (6:18 pm)
Is it surging on downhill off throttle with an AT? If so it could be the transmission doing a downhill decent engine braking thing. I know on my Armada and my Trooper both of which had a feature that will esentially add engine braking, surging the engine, if you completely remove your foot from the throttle.
#5 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [paisan]
Mar 18, 2007 (7:35 pm)
My 07 Outback does this as you describe, Mike, (with MT, even!) when holding speed or especially when taking foot off the throttle, and going downhill. It feels somewhat akin to a firm braking, then completely letting off the brakes, then firmly braking again. It is not a smooth process.
I do not think it is dangerous - certainly not an RPM surge - but it is acutely noticeable. I think I am getting used to it though because it does not seem as pronounced now as it did when "new."
#6 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [bkwaas]
Apr 11, 2007 (1:43 pm)
I have a 07 forester 5 speed. Going downhill w/ CC on it speeds up, going uphill it slows down, +/- 8mph. When not using the CC it is very sensitive to throttle imput from no throttle to very little throttle; it induces a jerky motion. This happens in any gear, at any speed, the more bumpy the road (thus more foot input to the throttle) the worse. At cruising speeds around sweeping corners in tight traffic this can be unnerving! The only answer is to put in the clutch, then let it back out smoothly. The fly by wire system is just too senstive at 0 to just on throttle! On a recent trip from PDX to LA the problem was magnified by a sticking hill holder clutch. I am getting somewhat used to it but it is very annoying. Worse than my '72 fiat spider I had back in college.
Nov 23, 2009 (10:03 pm)
I drive a 2008 black subaru forester manual base model.
My car did the exact same thing all time and i asked the dealer what was going on.
They were unsure at first and told me that they would contact subaru and get to the bottom of it.
I recieved a phone call three days later saying that there was a Re-flash available
I drove in the next day had the re-flash done and all was well.
I read the report about disconnecting the battery on here and then the problem came back
i found out that:
WHEN YOU DISCONNECT THE BATTERY IT RESETS THE COMPUTER AND ERASES THE RE-FLASH.
PLEASE IF YOU HAVE HAD THIS RE-FLASH DONE DO NOT DISCONNECT THE BATTERY. OR THEY WILL HAVE TO RE-FLASH IT AGAIN.
Good work and thanks for the advice
#8 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [bkwaas]
Nov 25, 2009 (5:16 pm)
"... contemplating buying a 2007 ForesterXT sports auto... I have read some disturbing things about a surging problem, at least in 2006 Foresters... traveling downhill..."
I have a 2008 Forester automatic. I had read about the surging not long after I bought the car new. I did not notice it until I read about it and went looking for it. I can barely feel it when coasting at slow to moderate speed against a light throttle. I don't feel it with throttle off. But in a long downhill coast against a light throttle, the engine feels like it alternates between the light throttle and off throttle. Surging is too strong a word, and I don't see what could be disturbing about it. Go take a test drive and see if you can even find it.
#9 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [aatherton]
Nov 26, 2009 (7:30 am)
I bet it's emissions related, something about the revs dropping too quickly.
#10 of 23 Re: Vehicle Speed Control/Surprise RPM Surge Issues [ateixeira]
Nov 26, 2009 (5:44 pm)
There are no revs to drop. The engine is coasting down a long hill at steady rpm against a light throttle.
That is, the throttle is less than what is needed to maintain the speed, and the engine is being pulled down the hill faster than the throttle.
If you take your foot off the gas, the effect stops.
I am never aware of it, and cannot feel it, unless I go to a place and make it happen. There is one long valley descent that I can hold 40 mph on, to feel it.