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Joined: Oct 2002
Posts: 2,408
R
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R
Joined: Oct 2002
Posts: 2,408
Low idle vacuum:
  • Major vacuum leak
  • Late ignition timing
  • Wrong static (cam) timing
  • Low compression
  • Mixture way off


Of course low compression is constant, ignition timing is non adjustable (unless it's always late because of a bad knock sensor), and static timing does not normally bounce around unless there is play somewhere like the cam sprocket bolts being loose.
Other things like collapsed lifters and sticking valves cause lots of vacuum bounce because it's only one cylinder doing it.
A large vacuum leak does not go well with smelling gas, nor does a leaky induction system causing a lean condition.

Keep thinking, and testing.


"Those who cannot remember the past are condemned to repeat it" -George Santayana
Joined: Aug 2002
Posts: 1,224
B
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B
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Thanks. It may actually get above 10 degrees this weekend, so I may have a chance to finally fix this.

I'm banking on the brake booster line being cracked.

I've been thinking more and more about it lately. At low rpm's it idles like complete and total crap. At high rpm's it runs GREAT. I mean even better than it usually runs. This would imply that I have unmetered air getting into the system, which would also be caused by a massive vacuum leak. It would cause my engine to run lean at higher rpm. This would actually help the high end performance but obviously hurt low end performance.

Last spring, I made a home-brewed intake out of that aluminum dryer hose stuff. It worked really well until the days leading up to it tearing open. I noticed more power in the upper rpm band and didn't know why. But one day when I came to a stop light my 'tour just died. I started it up but had to give it gas. I don't know why I didn't think of this before.

Enough of storytime, time to go get some

BP


Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies--- +++JRSC M62 Under Construction+++ My big-a$$ mod list.
Joined: Aug 2002
Posts: 1,224
B
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Its been a while..so here's an update (if anyone cares ).

My problem is definitly cold related. Ever since it has gotten out of the 30's, my car has been running just fine. There have been a couple of cold snaps and I will notice a little of the bad idle.

Tonight when I came home it was REALLY bad. I just wish that it would stay broken so that I could take it in and get it fixed.

Hopefully I will accidentally fix it through ripping my engine apart this summer and replacing all of the sensors that I haven't gotten to.

Later,
BP


Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies--- +++JRSC M62 Under Construction+++ My big-a$$ mod list.
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