Oil pressure during startup and RPM overshoot before stabilizing

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1,589
Location
Austin, TX
I use 5W30 Mobil1 non-synthetic for my Maxima and lately I have noticed during my first startup in the morning the engine revs upto 4000 RPM for sometime before stabilizing to 700 RPM (it actually screams while reving up to 4000 RPM). I know it has to do with the low oil pressure, any suggestions why it is all of a sudden -- oil changes have been regular. My guess is a faulty oil pressure switch but I could be wrong (no pressure light has popped up to my knowledge).
 
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22,188
Location
Colorado Springs
Ah, what? I do not think your oil pressure is related to your idle situation. You've got something else going on that's making your idle do that when first started, like a idle air control valve that sticks open slightly upon first start.
 
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3,858
Location
Cape Cod, MA
quote:
Originally posted by MaximaGuy: I use 5W30 Mobil1 non-synthetic
That's an oxymoron...all Mobil 1 oils are synthetic...maybe you meant Mobil Drive Clean? I agree with Drew99GT...and I bet it's not healthy for your engine to rev that high immediately after cold start-up...get it looked at pronto...
 

MaximaGuy

Thread starter
Messages
1,589
Location
Austin, TX
quote:

That's an oxymoron...all Mobil 1 oils are synthetic...maybe you meant Mobil Drive Clean? Yes, it is dino fluid. Thank you -- this weekend will keep me busy cleaning the throttle body as the ISC valve may not be passing enough air during idle -- buttefly plate may be dirty. I pray I don't have have to replace the valve itself.
 
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