What causes jerking on / off acceleration?

[Shibe 112]

My forester noticeably jerks when letting off the accelerator and when going back on, even when doing it extremely delicately. Coming off throttle, there's a short second then you feel like a surge / jerk. When applying throttle, it sort of jerks a bit heading back up the revs (rev gauge and move back and forward). Much more noticeable at lower speeds but still does it through the gears at higher speeds.

 

Sometimes second gear, having a tiny but constant amount of throttle applies, the car will jerk back and forward kinda violently while sitting over 2k rpm.

This was worse before I got it tuned, but it's still quite persistent. Reading up about could be a million things.. I've recently had spark plugs changed and the car scanned, which pulled no fault codes.

It's not a biggy, just makes driving slightly unenjoyable.

 

Edited November 17, 2020 by Shibe

[Joker 1,612]

maybe some upper engine cleaner OR stick throtle body?

 

What year / chassis?

[Shibe 112]

14 hours ago, Joker said:

maybe some upper engine cleaner OR stick throtle body?

 

What year / chassis?

 

2007 SH5, XT 5 Speed Manual

[Gripless 1,025]

I’d be running obd2 and checking the pedal and throttle readings dont leap around. 
 

[Shibe 112]

16 hours ago, Gripless said:

I’d be running obd2 and checking the pedal and throttle readings dont leap around. 
 

Have just ordered me an OBD2. Will give them a look once it arrives.

[Shibe 112]

Quick follow up: Upper engine cleaner has made a massive improvement. 

[Gripless 1,025]

In that case you may want to go look at the fuel filters 

[Shibe 112]

3 hours ago, Gripless said:

In that case you may want to go look at the fuel filters 

 

Explain? 😁 

[Gripless 1,025]

If dissolving s*** in the fuel helps then you likely had some crap building up somewhere.