Forester turbo 2001 ej205 engine, needing some help with a misfire type thing, doesn't happen when giving it a proper thrash all through the gears but say country roads and a spirited but sensible driving style it misses, at least it feels like a missfire, I tried moving the knock sensor back onto the bell housing and it seemed better for a month or so but it's back again, so thinking it's something along them lines, what causes the knock sensor to pick up a fault? Had new plugs, air and fuel filter, can't find any leaks anywhere, no engine light or codes, just been on holiday with it and done 1000 miles this last week and it's not got any worse or had any other problems, can't even notice it when driving normally but putting it under loads sometimes seems to make it miss, sorry for the length and vagueness but hopefully someone will have an idea.

P. S. What happens if boost solenoid isn't working?

If the boost solenoid isn't working you will get a BIG lag when driving, easiest way to explain it would be like doing a quick emergency stop and going again!! Lol

I had this problem, but I found a pipe not connected that was causing my lag.

You've said you've done the air/fuel filter and plugs so that's good, Mass sensor and Boost solenoid might need cleaning?? Some guys told me this could be causing this too?? - worth a try?? Good old elbow grease!!! :D

Yer I've tried cleaning those, I've connected my connectors under the dash and my boost solenoid didn't 'click' and when I sprayed some brake cleaner into one end it didn't come through the other, so I'm thinking it's not working but then it goes better than I'd expect if it wasn't working, anyone know any other ways of testing it? Don't have a spare one to try unfortunately

Weird???

Might seem silly but have disconnected the battery??

My only changed after resetting the Ecu by disconnecting the battery and connecting again after a few minutes then all was fine again?

Other than that - it's a weird one this

Yep done that as well haha, it's definitely a wierd one, just trying to make sure I've covered everything before getting robbed by subaru

I presume you only have the one set of plugs under the dash ?

As for the boost solinoid, is it a two port or three port one ? (The number of hoses in and out)

I'd have another go at cleaning but spray spray and spray some more until it comes out. What fuel are you running it on ?

It's a 2 port solenoid, there's 2 green plugs under the dash and 2 black plugs, I think it was the green ones I joined, it made a load of things click and work etc under the bonnet, and primarily just running it on standard shell, I did run a good few tanks of v power trough it but that didn't make any difference

Ptry it with both sets of plugs connected, did the fans come on when you did it the 1st time ?

Yer fan came on, didn't know what the other plugs did so didn't want to connect them

I've had another look this morning at my plugs and can only find one black plug that's near the 2 green ones, anyone know if I'm just missing the other end or will it be for something unrelated?

You'll have odb 2 the older cars had two sets of plugs black for code reading and green for diagnostic, yours will just have the one,

If the fans come on then you've plugged the connector in properly,

I'd have another go with them plugged in and the ign to acc and spray some more cleaner in

Spot on I'll do that later, I think the local scrappy has one of these in so gonna go and nick the boost solenoid just to try