Sluggish when cold, Injectors?

[andyhessler]

My 1997 Legacy L wagon seems to hesitate when accelerating when it's cold and then runs like a champ when it's warmed up a bit. It's done this to some degree since I bought it at 114k. Now at 174k it's showing some signs of degraded gas mileage and more of a tendency to buck and run rough.

 

When I accelerate hard, like on the freeway, it takes off like there's no tomorrow. Fuel filter is ok and changed regularly. I put new plugs yesterday in and new wires a little while ago. It would seem odd if the pressure regulator is bad since the idle noise changes noticeably when I remove the vac hose. And I can't imagine the fuel pump being bad while I can still accelerate hard when I need to. It's just when I pull away from a stop light it kind of just chokes and then surges back to life. Then it runs just a little rough until it warms up.

 

I'm planning on buying some rebuilt injectors...and crossing my fingers. Any other ideas would sure help. Thanks.

 

I'm new to the forum. Please bear with me. (Yes, this is all I have to do on Christmas Eve!) Merry Christmas.

[Richard1296]

I would look at the coolant temperature sensor or the

oxygen sensor as the two most likely causes.

Have you checked it for trouble codes ?

 

Richard

[nipper]

Injectors are the last thing to suspect. It's akin to wanting a heart transplant cause you have a cold.

When was the last time this car had a tuneup, filters changed, and an o2 sensor change?

 

nipper

[Manarius]

My car is a dog when it's cold. The fact is that the tranny fluid is cold and the car just isn't up to driving like a bat out of hell when the tranny isn't warmed up. I think this sort of idea can be applied to your car as well.

 

However, the above mentioned sensors may be able to help you out slightly if your car is really slow.

[andyhessler]

Seems like the O2 sensor will be a good place to look. The filters are replaced pretty regularly. And, when I say 'cold', it's just that it hasn't been running...not that the outside air temp is really cold. Today I drove it and it seemed to be much happier with some Front Transaxel gear oil being added and of course the new plugs. Still the same issue exists but maybe to a little lesser degree. I'll have to read up on what this site says about the O2 sensor. I'll let you know how the hear transplant goes.

Thanks,

[andyhessler]

Well,

I bought injectors...that turned out to be the wrong ones. So, I ended up returning them (so to say). I saw some discoloration on the one injector I did remove. It was very asymetrical in that only a 1/4 of the nose of the injector nozzel was showing this pattern. Anyone have experience with that?

I didn't get to inspect the other ones. (quite a bear to pluck then out).

 

Thanks!

 

(There's snow on the ground! Which makes a Suby driver very happy in deed!)

[OB99W]

Seems like the O2 sensor will be a good place to look. The filters are replaced pretty regularly. And, when I say 'cold', it's just that it hasn't been running...not that the outside air temp is really cold. [...]

 

Well, I bought injectors...

[...]

(quite a bear to pluck then out).

 

If by "cold" you mean immediately upon starting, then an oxygen sensor problem isn't a likely cause; the engine management runs "open loop" (using default settings and ignoring certain sensors) until things warm up a bit.

 

Not that injectors are the likely culprit, but here's a bit of help in getting some of them to be a bit more cooperative:

http://endwrench.com/images/pdfs/ProperInsideEWFall05.pdf

 

You might want to check whether there's any corrosion on the ignition wire terminals, both at the plugs and the coil pack; Subarus seem to be somewhat more touchy than average about that, especially when the engine is cold. Also, when you replaced the wires, did you use OEM? Many of the aftermarket ones aren't up to the job.

[weddes05]

when was the last time you did a knock sensor?