Have what would seem a silly question for most but here goes. I recently had occasion to take the engine out of my 96 Impreza outback,which I have done a couple of times before.Usually I take pictures to make sure bits go back in the right places but this time I forgot.My question: Which nipple on the manifold do the two vacuum pipes from the pressure sensor and the pressure source switching solenoid valve go to.One of them has a filter thingy on it and the other doesn't. Could this cause rough running or a misfire if wrongly connected?

Edited April 24, 20205 yr by Bassboy81
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There is a sticker on the hood that shows the routing.

Unfortunately not on mine,it fell off years ago.

 

have you checked FSM for the info?

you can find one here: http://jdmfsm.info/Auto/Japan/Subaru/

 

Google image search picture of under hood sticker or engines online. 

the length and deformity of the hose,  installed on parts mounted as they were originally, often tell the story.  look at the ends and any mount/touch/rub,clip points.

In the end it shouldn’t matter - vacuum is vacuum. The hose doesn’t know, or care, where it’s coming from. It’s like asking if you should use gas pumps facing the north or south? Doesn’t matter. 

if you suspect them causing issues the chief non-start cause is a loose vacuum hose that’s leaking and pulling in unmetered air. It’s usually the brake booster hose not installed, loose, cracked. So make sure none of the hoses are leaking  

It’s not likely to be your issue but If you suspect those vacuum hoses or want to check them, it’s not going to be their location of installation.  blow out or clean the hoses in case any debris or bugs got in there during the down time.  But that’s doubtful the issue. 

if you’re chasing rough running or misfire then diagnose that separately. A true misfire ( get a check engine light) on that is usually caused by plugs and wires or less commonly the coil pack. 

that engine is not very forgiving of cheap or non OEM plugs and wires. Use stock NGK plugs and NGK or OEM wires or other notable quality parts. 

Edited April 26, 20205 yr by idosubaru

Thanks for the reply Ido,I have the vacuum pipe issue sorted but it did not change anything I don' have a nostart issue,just a persistent misfire when warmed up and under load if I'm very light with the foot I can get all the way up to 2000rpmin top gear as long as I don't come to a hill.I fitted new plugs when I put the engine back in and yesterday I fitted new HT leads,as to my knowledge they had never been renewed.It's a bit mystifying as the engine was running like a champ up until I pulled it to fix some oil leaks.She is definitely running on all four so I'm inclined toward a fuel delivery problem of some kind.Is it at all possible that If I had one tooth error on the timing belt it would have that effect? As I said earlier it's fine until it gets up to normal running temp.Sorry to be longwinded but I'm banging my head on the wall here.

Did you get the coolant temp sensor plugged in?

Both of them.  One is for the dash, the other for the ECU.

Pretty sure I hooked them up but I will check again in the morning.