2 litre quad cam Leggy - which petrol

[Lotobear]

My recently acquired UK 2.0 petrol Legacy (09 MY) has the dreaded flat spot/hesitation between 2-3krpm.

I decided to fill it with Tesco Momentum 99 which initially made it much worse however once the tank got to below 1/2 full it started to improve and now runs better than ever.

Have I fixed it or was there never a problem in the first place? I think the PO was running it on standard 95ron but the service record shows a PAK update and various sensors over the last few years - oxygen, MAF etc. so there seems to have been an issue.

Anyone have experience of this 'issue'?

[GravelBen]

I'd think it should be fine on 95, but may run a bit nicer on 99. Mine have all been older models though so someone else may have more specific advice for that age of car.

I'd suggest giving the MAF a clean to start with anyway just out of principle.

Edited by GravelBen on Saturday 12th May 00:21

[74merc]

I have the same engine in a Forester. It had all the PAK updates but none of them made any difference. I spoke to a dealer about it and they reckoned it was due to electromagnetic interference with the knock sensor. I did the ECU reset and always set my phone to flight mode when in the car. It made a huge difference and minimised the hesitation. Without setting the phone to flight mode, the hesitation would return within about 250 miles of an ECU reset.

[rastapasta]

74merc said:

I have the same engine in a Forester. It had all the PAK updates but none of them made any difference. I spoke to a dealer about it and they reckoned it was due to electromagnetic interference with the knock sensor. I did the ECU reset and always set my phone to flight mode when in the car. It made a huge difference and minimised the hesitation. Without setting the phone to flight mode, the hesitation would return within about 250 miles of an ECU reset.

I have this engine in a 2013 model Leggy. I too noticed the hesitation. The damn thing is dead at times between these rpm brackets. Only gets going at 3k rpm and i have had people say they have noticed the slight kick. My theory was the outside temperature. I always found mine goes better when the outside temp is between 10-22 degrees with the sweet spot being 13-17 degrees. But to be honest this is probably BS as I was looking for anything to explain it. I even had the garage adjust the A/C as I thought it was eating the power and causing the dead spot. Im not going to bother doing an ECU reset as I can bypass the dead spot by dropping the car into a lower gear and revving the nuts off it but I will try the airplane mode trick.

[rastapasta]

Lotobear said:

My recently acquired UK 2.0 petrol Legacy (09 MY) has the dreaded flat spot/hesitation between 2-3krpm.

I decided to fill it with Tesco Momentum 99 which initially made it much worse however once the tank got to below 1/2 full it started to improve and now runs better than ever.

Have I fixed it or was there never a problem in the first place? I think the PO was running it on standard 95ron but the service record shows a PAK update and various sensors over the last few years - oxygen, MAF etc. so there seems to have been an issue.

Anyone have experience of this 'issue'?

I've noticed the suck alright. The legacy suffers in a way due to not having a turbo in this regard. I think this issue is perhaps the trade off for having such a reliable engine in the general sense. As a matter of course, i put 98 into it every 4/5 fill to clean the engine. I am not sure this will have any discernible benefit save for the fact that I am at 94k in km and haven't had any issues with the car in this or any other regard in fact.

[Lotobear]

Interesting comments.

I tried the airplane mode trick yesterday to no effect.

I would however concur that air temp appears key - it runs very well in colder conditions but in warmer weather it gets the dead thing between 2 and 3krpm. Also, it doesn't occur when the engine is cold.

I may change the MAP sensor

[rastapasta]

Lotobear said:

Interesting comments.

I tried the airplane mode trick yesterday to no effect.

I would however concur that air temp appears key - it runs very well in colder conditions but in warmer weather it gets the dead thing between 2 and 3krpm. Also, it doesn't occur when the engine is cold.

I may change the MAP sensor

Its not great when it goes into the minus figures temp wise. But at the same time when thats going on im too focused on dodging other heads in the snow to take much notice.

As a general comment, Ive had mine for a while and have not one issue with it. Its a bit awkward in traffic The Bluetooth is a bit fiddly to set up and there are some build quality issues such as the boot cargo cover having a clip that falls off every time you use it and the cup holders having a partition piece that comes out whenever you but a large water bottle in it. The Awd system lets you really push it into the corners and it grips forever. Torque isnt particularly great but they have a good top end. The Manual gearbox is notchy at first and takes some getting used to. But honestly they are beasts on the road and will conceivably allow you in poor road conditions to leave the posse behind. In normal conditions they are not the fastest on the road but certainly not the slowest. They are quite hard to drive with the Awd in traffic as its a permanent system and so the car can be quite jumpy at low speeds. But otherwise the system is simpler and yet far far superior than the Haldex systems on for example VW group cars. If you need to know anything more then PM me.

[Lotobear]

Cheers Rasta,

I'm a returning fan - had 2 gen 4's previously all from new, then an A4 Allroad and then 3 Skodas.

My first was a 2.5 manual RE (rare in a Legacy) which was great and the second a 2.0RE which is what I have now albeit the detuned 150bhp version.

Of all of them I liked the 2.5 - simple and torquey, and better economy than the 2.0 but it's nice to be back in one either way.

[rastapasta]

Lotobear said:

Cheers Rasta,

I'm a returning fan - had 2 gen 4's previously all from new, then an A4 Allroad and then 3 Skodas.

My first was a 2.5 manual RE (rare in a Legacy) which was great and the second a 2.0RE which is what I have now albeit the detuned 150bhp version.

Of all of them I liked the 2.5 - simple and torquey, and better economy than the 2.0 but it's nice to be back in one either way.

true enough. we have a Forester XT that my wife drives that has the 2.5 @ 245bhp. Its nice and quick but it reminds me of my first car which was a fiat punto in that Im always paranoid that the dreaded white scum will appear on the engine with the cylinder head gaskets giving out.

[Lotobear]

..the 2.5 UK Legacy was n/a - 162bhp so no worries about head gaskets. Simple SOHC with nice torque and lazy feel to it, prefer it to the quad cam.

[74merc]

Lotobear said:

Interesting comments.

I tried the airplane mode trick yesterday to no effect.

I would however concur that air temp appears key - it runs very well in colder conditions but in warmer weather it gets the dead thing between 2 and 3krpm. Also, it doesn't occur when the engine is cold.

I may change the MAP sensor

I found the airplane mode only works after an ECU reset. It's worth a try, disconnect the battery for at least 20 minutes. Reconnect then leave the ignition on but without starting the car for 1 minute. It's a drive by wire throttle so takes a while to calibrate itself. Start the car and leaving it running for a while.
I bought a new genuine MAP sensor for mine for £250 and it made no difference whatsoever.