Runs rough then fine......

[jp260z]

Hello, I'm new to this forum. I have a 91 Legacy L (N/A....not sure if the L even came in turbo trim) and I have a nagging problem that has me baffled. I was wondering if anyone out there has had this problem already and solved it. My car starts up and runs like she's only hitting on two cylinders for a good 20 seconds....then she mellows out and runs fine.

This happens when its warm and when its cold.

Jay

[ciper]

Can you recreate it everytime? Id park your car in the darkest place possible and have someone start it while you watch under the hood for sparks.
Is the idle speed the same before and after it runs like this?
Do you turn the key on for a few seconds before starting it?

[jp260z]

Yes 9 out of 10 times I start it she does this. I haven't tried looking for sparks, that's a good idea.....although if it was arching it would probably do it all the time, in otherwords she'd always run rough. I was wondering if the Legacy's have a problem with fuel injectors leaking, causing the motor to load up when turned off, thus making the car run rough for a couple seconds when started...until the extra fuel is burned off, which would then allow the car to run fine again.

But then I thought about the cold start valve malfunctioning. If that wasn't kicking out extra fuel for cold starts, then she'd run rough (or not at all). But see, it runs rough when I start it warm too....which a non functioning cold start valve would not affect.

I am going to try looking for sparks and go from there.

Thanks for the reply!

Jay

[vrg3]

It could be a leaky injector seal, yes...

There isn't a cold start valve; the engine computer just lengthens injector pulse width when coolant temperature is low.

[slickmasterc]

when was the last time it had a oil and filter change. cos my mates mitsi was doing the same thing, but once he change the oil and filter it ran fine(note the previous owner used a heavyer oil in a turbo engine, not a good idea)

[jp260z]

OK, found my problem and I wish it was as simple as an oil change. Sadly, the legacy has developed a cracked head and is sucking in coolant, causing it to run rough initially, then smooth out after awhile. She now turns up about a gallon of coolant short every other week, which is when she then starts running hot.

I am replacing the engine with a 94 Legacy motor that currently runs fine, the car it is coming out of was hit hard in the back and is totaled. I don't know a lot about Subaru's but I'm hoping this 94 motor has a little more power than the 91 motor it is replacing. Of course my main concern is just to get her running good again.

Thanks for the help,

Jay

91 Legacy L ....soon to receive a new heart (94 motor)

[THAWA]

same engine/power unless it was a turbo car