2001 Legacy

[Vmech]

Hello folks,

I could use some help.

I have several problems 

 

2001 Legacy hatchback automatic transmission.

 

Thumping of driveshaft/transmission(?) in first gear (I think). Like a drum roll with 5-8 thumps then fine. It feels like it is coming from the middle of the vehicle just behind the front seats.  Also I can hear a very faint high pitched metal on metal scraping when crawling forward. 

 

Smell of fuel in cabin compartment when in idle. 

 

Scariest of all a the car struggling on acceleration and  pushing back (like being in to low a gear) then slightly accelerates a couple times. The tachometer bounces up and down a little reflecting struggling of engine/transmission(?). The check engine light flashes during this Shifting in to neutral then back in to drive while still moving corrects this.

 

When ever I shift into drive even when stopped the car starts to idle roughly 

 

I have not had the error codes read before the this last problem occurred

 

and they where and Evap system leak small (P0442) and a Knock Sensor (P0327)  

 

I am just trying to get a better idea of what  the problems are

 

Oil is good (although I have a small oil leak which I will try and address if the other problems are not fatal)

Transaxle fluid level is good. I changed it about a year ago

 

Going to do the usual things

Change

spark plugs/ cables

fuel filters

PCV valve

and investigate the EGR

 

Any help would be appreciated

 

[nipper]

How many miles.

 

Thumping needs to be looked at asap. That can be a driveshaft issue.

Scraping noise can be the driveshaft or brake pads or a stone in the calipers

Smell of fuel can be the rubber fuel lines from the fuel rail to the injectors or thier clamps. This is a common thing to happen especially in winter.

 

Not sure about the next one, but lets rule out torque bind. Do all the tires match, equally worn, properly inflated. How does the car behave when you drive in a circle.

 

Knock sensor can account for the rough idle and running issues. For a simple little sensor it can do a lot of mischief  

[Vmech]

182,235+

brake pads replaced in the last 6 months

Yes all tires bought at the same time and properly inflated

driving in circle it behaves fine

I have noted that the knock sensor can be a pain but considering the age and condition of the car it may be accurate where is it located and what does it measure

[nipper]

Brake pads can pick up a stone at any time, especially when roads are sanded. It is just annoying and may need it to be removed if it doesnt clear itself. It can also be a backing plate rubbing.

 

That mileage, yes check the drive shaft asap.

 

http://www.ultimatesubaru.org/forum/topic/116520-knock-sensor-101-and-replacement/

[Vmech]

copy that, unlikely sand or stone they don't sand roads here and I dont drive offroad. Thank you that narrows things a bit

[Fairtax4me]

Did you replace front and rear brake pads? Did you clean and re-grease the caliper slide pins?

 

Flashing CEL means its misfiring. NGK plugs and wires should cure that. This could create the "thumping" feeling when trying to accelerate.

 

Knock sensors go bad all the time and are easy to replace. Search for my "Knock sensor 101" thread.

[1 Lucky Texan]

frozen u-joint or possibly carrier bearing problem.

 

fuel smell and evap 'could' be related. Sometimes the fuel filler neck has corroded holes behind the plastic.

Edited February 7, 2014 by 1 Lucky Texan

[Vmech]

Thank you all this great info!

[unibrook]

 

Fuel Filler Neck – CEL:  P0442

Bot new neck pipe on Ebay.  Hoses, screws, hose clamps...you will get at
AutoZone.  The new check valve
you get at Subaru dealer.  Some of the
mounting bolts might be frozen, but tap them with hammer and wood and spray
with WD40 for 15 minutes before cranking them off might help.  The hardest part for me was trying to
separate the hoses from the corroded steel pipes and lines.  All seemed impossible.  I suppose you could saw apart the old rusted filler
neck and get some swing room that way to twist it out of the rubber hose
connecting to the gas tank.

[AdventureSubaru]

Lots of good suggestions so far. I wouldn't start throwing a lot of parts at it just yet. Try and narrow things down as you could have a large issue or a couple minor ones.

 

Step 1 - get under the car and look at the joint of your driveshaft and check it for play. Look inside the joint for sheared metal and anything amiss. If there is, you probably have your thumping problem figured out. My driveshaft was ready to tear itself in half and the car would lurch and bouch with some nice clanking sounds before I could safely pull over and found the problem. (I ended up pulling the driveshaft in a dennys parking lot, capping the back of the trans and driving home in front wheel drive.)

 

Step 2 - new plugs, wires and knock sensor. get rid of your misfire so you can weed out other things. Knock sensors can really make your car act goofy. Plugs and wires are good maintenance anyway.

 

See where you sit after those things are checked.