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Hard starting Cold & lean stumble 99 OB


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For those searching on this problem as I did...

 

Cold starting was hard; didn't even have to

be that cold. Backfiring and poor drivability

until warm, then OK.

 

No check engine light.

 

Based on previous suggestions, I replaced the

coolant temperature sensor. That completely

fixed it. Good thing, too, I'm not sure what I

would have tried next.

 

BTW, getting to the thing is a b*tch. I once

did it on my '95 impreza and couldn't remember just

how. This article was most

helpful! Step by step photos.

 

www.lovehorsepower.com/SubaruDocs/CoolantTempSensor.html

 

Those hoses didn't just slip off, however!

 

Bill Hale Loveland CO

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  • 4 weeks later...

Well, bad news. The fix didn't really work. So I am looking for

what would be next. I am pretty sure nothing is leaking.

 

Any suggestions? I'd even take a good hunch. There must

be lore on how to fix this.

 

Tnx, Bill Hale

 

 

For those searching on this problem as I did...

 

Cold starting was hard; didn't even have to

be that cold. Backfiring and poor drivability

until warm, then OK.

 

No check engine light.

 

Based on previous suggestions, I replaced the

coolant temperature sensor. That completely

fixed it. Good thing, too, I'm not sure what I

would have tried next.

 

BTW, getting to the thing is a b*tch. I once

did it on my '95 impreza and couldn't remember just

how. This article was most

helpful! Step by step photos.

 

www.lovehorsepower.com/SubaruDocs/CoolantTempSensor.html

 

Those hoses didn't just slip off, however!

 

Bill Hale Loveland CO

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Well, bad news. The fix didn't really work. So I am looking for

what would be next.[...]

If replacing the CTS seemed to cure the problem for a while, it might be that the connector is corroded. (Lots of sensors get replaced when it's actually a connection to them that's faulty.) I'd verify that's good (at least by visual inspection) before any further diagnosis. You could try removing and reconnecting it a few times, which often scrapes off corrosion, and see if that helps.

 

If the current problem isn't too severe, this might explain the cause:

http://endwrench.com/images/pdfs/LegacyIdleSum04.pdf

 

Keep in mind that problems which only slightly affect operation when the engine is warm may be much more evident when it's cold. Is it completely "OK" when warmed?

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Well, bad news. The fix didn't really work. So I am looking for

what would be next. I am pretty sure nothing is leaking.

 

Any suggestions? I'd even take a good hunch. There must

be lore on how to fix this.

 

Tnx, Bill Hale

Did you disconnect the battery while doing the work, therby resetting the ECU to stock? Are you sure your CEL light is working? Plugs and wires, maybe?

 

IMExperience, 95% of all fuel problems (suspected) are ignition problems (actual).

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