Something to worry about?
06-11-2011, 08:14 PM
#1
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Something to worry about?
Hey guys,
I took the Miata up island last weekend and back (250km each way), on the highway. I noticed something odd and just wanted to run it by everyone here to see if they thought it was something that I should worry about.
Cruising on the highway doing 130km/h @ 3800k RPM I noticed the odd RPM dip - the revs would, without rhyme or reason, dip from 3800k to 3000k for a split second before continuing on its merry way. On the entire trip, it did this 4 or 5 times that I noticed. I'm not really sure what it might have been, perhaps fuel cut?
Is this something that I should look into further or that I should be worried about? Or is this a common occurrence?
Thanks.
I took the Miata up island last weekend and back (250km each way), on the highway. I noticed something odd and just wanted to run it by everyone here to see if they thought it was something that I should worry about.
Cruising on the highway doing 130km/h @ 3800k RPM I noticed the odd RPM dip - the revs would, without rhyme or reason, dip from 3800k to 3000k for a split second before continuing on its merry way. On the entire trip, it did this 4 or 5 times that I noticed. I'm not really sure what it might have been, perhaps fuel cut?
Is this something that I should look into further or that I should be worried about? Or is this a common occurrence?
Thanks.
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06-11-2011, 10:46 PM
#3
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Something similar happened to me. I eventually realized I was in 4th instead of 5th and cruise control didn't like that. It was like the turbo kept wanting to spool but the engine was like "Hey we're going fast enough. Chill out."
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06-11-2011, 11:36 PM
#9
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An 800rpm drop is like a 12-15mph drop in speed. It's not "hard to say" whether that happened or not. 
If you are getting an 800rpm tach drop and a small misfire, it's just that - a misfire. Change the plugs/wires and then look to ECU grounding or cam/crank sensor issues.
If you are getting an 800rpm tach drop and a small misfire, it's just that - a misfire. Change the plugs/wires and then look to ECU grounding or cam/crank sensor issues.
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06-11-2011, 11:51 PM
#10
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No a/c.
It not quite that dramatic. Its only over a fraction of a second and the speed loss isn't noticeable.
As far as changing the plugs/wires and all that other stuff... any recommendations for how-to's, tutorials, etc.? I don't exactly have much mechanical experience, or really any... at all
It not quite that dramatic. Its only over a fraction of a second and the speed loss isn't noticeable.
As far as changing the plugs/wires and all that other stuff... any recommendations for how-to's, tutorials, etc.? I don't exactly have much mechanical experience, or really any... at all
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06-12-2011, 12:33 AM
#12
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Does ~500m count as a major altitude change? Although it happened before I hit the altitude change...
Also, wouldn't this oddity happen when cruising around the city? The only time I noticed it was on the highway and only in 5th at constant RPM.
Also, wouldn't this oddity happen when cruising around the city? The only time I noticed it was on the highway and only in 5th at constant RPM.
Last edited by UnknownPerson; 06-12-2011 at 12:52 AM.
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