2004 Forester - What's with the "lumpy" acceleration?

Question

I've got 4000km on my 2004 Forester 2.5XS (5spd manual). Moderate acceleration from 2600rpm through about 3700rpm is lumpy. Lumpy is probably the best way to describe it. Whatever it is, it is definately not smooth acceleration. Operating and shifting at 4000+rpm, the engine sounds strained, like it's time to shift. Occasionaly I have noticed rough idle when sitting at a stop light. Any ideas?

My 90 Legacy with 2.2 (5spd manual) certainly doesn't have this lumpy acceleration and the shift rpms I use in it are 2500 - 3300rpm, depending on acceleration requirements. The 2.2, though 15years and 180,000km older feels like it produces better and smoother power, even in the heavier car. mmm?

Edward Hayes · Accepted Answer

My 2000 Forester 70,000 miles has never had this problem. A bad load of gas???

gringo · Answer

clogged fuel filter?

H · Answer

from the same high-volume supplier. Never had problems with my othervehicles.

Ken Gilbert · Answer

reset the ecu by disconnecting battery and waiting for a while.  thentest drive again.ken

Brian · Answer

Are you running the A/C?  The A/C will bog down my Outback H6 in the mid RPMrange.Brian.

Tony Hwang · Answer

Hi,You mean tach needle is not steady when idling?Then something is not right.Tony

Tony Hwang · Answer

Hi,When a/c comes on ECU automatically compesates raising rpm. What do you mean bogging down? You can hear and feel a/c compressor engage butit shouldn't bog the eingine down. some cars temporarily disengagea/c compressor clutch when quick acceleration is called for.(like passing)Tony

forsale · Answer

Could it be some knock sensor issues causing intermittent retarded timing?

Tha Ghee · Answer

are you using the proper octane of gas??

H · Answer

are you using the proper octane of gas??

I'm using 87 octane as required. No pinging or other signs of octane problems. I'm about 1500km from it's initial 6K service so we'll try to sort out some of the little nags the vehicle has. My console power outlet doesn't work either.

Jim85CJ · Answer

Are you using 87 octane?  I tried premium gas once and my performance was shot.  Took two fill-ups to restore back to normal.H wrote:

2004 Forester - What's with the "lumpy" acceleration?

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