Jump to content
Ultimate Subaru Message Board
Frank T

87 GL Vibration 2500-3500RPM

Recommended Posts

87 GL10 Wagon

Fuel injected



53K original miles


I have a nasty vibration between 2500-3500 rpm when accelerating up a hill. It happens in any gear and will go away instantly if I take my foot off the gas just a little bit (still accelerating but not as hard). But if I put it back down it comes back instantly.  It feels like the car has a rev limiter on it and its dropping a cylinder. Most of the time I just take my foot off the gas or smash it to the floor to get the trans to down shift to get past the vibration. But I was on a trip recently where I was climbing a very steep hill and had to keep the pedal on the floor. It vibrated alot from 2900-3200 RPM, but kept accelerating (not as well as normal) until I got the RPMs above 3300, then it accelerated well and the vibration was gone.


I swapped tires and rims around but nothing changed. I changed the air and fuel filters, no change. I changed both front axles and wheel bearings due to ripped boots and I was hoping this issue was related to the axles but there is still no change in the vibration. Also I changed the timing belts about 6K miles ago. I feel like it has something to do with the fuel injection or the trans/torque converter.


I feel like I can live with it but I dont want it to be a sign of some catastrophic failure of sorts down the road.


Any ideas?



Frank T


Share this post

Link to post
Share on other sites

sounds like my clutch.  have you checked your trans fluid?  maybe theres a weak point in the system where its trying to shift and can't.  do you think its motor related?  vibration is a bit generic.

Share this post

Link to post
Share on other sites

Do you hear any mis-firing when it happens? Is the engine running smooth? Backfires, popping, etc?

Have you tried shifting through the gears manually and, if so, does that help?

Has it always done it since you've gotten the car?

53k, that's just about where my car was  when I got it :)

Check your transmission fluid.

Share this post

Link to post
Share on other sites

Check the timing and adjust as required.

Clean the pcv valve with brake cleaner.

Lightly sand the corrosion off of the points in the distributor cap and the end of the rotor.

Check the distributor cap top holes for corrosion that you can scrape out with a screwdriver.

Check both ends of each plug wire for corrosion.  Sand corrosion off.

Install new plugs.

Buy better gas.

Edited by scoobiedubie

Share this post

Link to post
Share on other sites

Sorry for the generic 'vibration' description.


Yes it has always done this. When I got the car it had lost its fan and it destroyed the
radiator. So while I was in there fixing that I figured I would change the
timing belts since I already had the front of the engine apart.

I feel like it has something to do with the transmission or fuel injection, since it does it
only under acceleration (very noticeable going up a hill)... come to think of
it, it acts like pre-detonation (but way worse) like its trying to fire the
cylinder but the timing is off or its starving for fuel. Any thoughts on this?

I was paying close attention to it this weekend and I could get it to do it at RPM’s as low
as 2200. But as soon as I lifted my foot it went away.

Thanks for all the suggestions. Ill run through these this weekend and report back.

Share this post

Link to post
Share on other sites

Double check your timing belts.  It's easy to get them off a tooth when replacing them.  There is a sequence when putting the belts on.

Driver's side -

With the tensioner in the loose position (bolts tight), install the driver side timing belt to crankshaft sprocket, oil pump sprocket, idler and then camshaft sprocket IN SEQUENCE.  With belt in place, loosen up the tensioner bolts.  The spring will take up the slack.  Apply18 lbs torque counterclockwise to camshaft sprocket and tighten the tension bolts (14 lbs).  Now double check to see if flywheel hash marks and camshaft sprocket are still in their correct starting positions.

Passenger Side:

Rotate the engine 1 revolution clockwise...lining up to center hash mark.  Align camshaft sprocket extra hole to notch on rear plastic belt cover OR if no plastic cover then line up to vertical valve cover seam).  Attach timing belt to crankshaft sprocket, around tensioner then to camshaft sprocket in that order.  Loosen tensioner to apply tension to belt.  Apply 18 lbs torque counterclockwise to cam sprocket and tighten tensioner bolts to 14 lbs.

Hope this helps.

Share this post

Link to post
Share on other sites

Check the ignition advance. It should be 20 deg btdc. To check the static timing, the green diagnosis plugs need to be connected. IF they are connected already, they should be unplugged for normal operation. the green test plugs are located under the steering wheel hanging out by the ecu for 1987 harness

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now