Subaru Forester Owners Forum banner

2010 - HELP after tuneup car is running worse? (merged thread)

('09-'13) 
4K views 39 replies 12 participants last post by  justinw2116 
#1 ·
Hello new to community. We have had Subaru’s for over 20 years now. Our 2010 forester had thrown a mis fire cylinder 4 code. We changed plugs and wires check engine light is gone but car is running very badly. First no check engine light now, can’t rev past 4000rpm in park or neutral, slow take off, not shifting right, we hear a slight whooshing noise when driving. Shifting 1-2 are very slow at right rpm but 3-4 tac to 4500 then shift. Can’t seem to get to 50. Transmission fuel is full,clean, and no smells. Thanks for any info we are at a loss. If you need more info I will do my best to answer.
 
#32 ·
Have them check for an exhaust system leak. If it's after the 02 sensors, it may not cause a code, but it will affect your acceleration. And as others have pointed an air intake leak seems like the likely culprit.

Keeping my fingers crossed for you. I hope it can be resolved relatively cheaply.
 
#38 ·
Right, but my question remains, worded differently: does a new car require an idle relearn after swapping out a battery?
 
#40 ·
I can't speak to "a new car". I imagine that every manufacturer has their own recommended procedure for battery replacement. Mine required it because of how dead the battery was. I have never heard of idle re-learn being required for my 2010 after battery swaps. But if the car is running like crap after spark plug/ignition coil/battery I would definitely do an idle-relearn, it is a free diagnostic that can be done in the driveway.
 
#39 ·
Do your brakes work fine? Do they feel normal? as in, you don’t have to push really hard to get them to stop properly.

If your brakes are working well, it’s likely the vacuum brake boost is too. So a vacuum leak from that perspective, is less likely.

If spark plug leads are falling off, you can slightly crimp the metal terminal, so it fits tighter.

Being slow to take off, slow to shift, and won’t rev past certain rpm in Park/Neutral, might suggest lock up converter is not unlocking (faulty lock up clutch solenoid in torque converter).

Whooshing sound could be transmission fluid/pressure.

If 4EAT I believe changing solenoids is easier/possible on the solenoid control module.
 
You have insufficient privileges to reply here.
Top