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Bad mpg

T

toby

New member
I have a 97 grand prix with 136 mile with a 3800.I am getting 12-14 mpg in town I have put new plug and wire and a new fuel pump and fuel filter 800 miles a go.All fuel pressure are good And some times it crank 5-6 times before it starts No CEL come up beside that it run good. new o2 sensor and cat is good. thank you
 




could my lower intake manifold gasket be bad the upper intake manifold plenum and gasket was replace no lost of coolant that i can See or sweet odor
 
do you KNOW the cat is good? Changing the PCV valve might help.

On average, whats the highest RPM the engine revs to in first gear?
 
The cat is good and pcv was done at tune up. 700-800 hundred in 1st. 1800 hundred at 60 mph could my trouble be my drive to work is 2 to 3 miles every day?
 
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Sorry man, i need some punctuation in there to understand all that.

What I mean is when the car is accelerating what is the highest RPM the engine gets to?

Also if you're just stopping every time you get up to speed, you'll have crappy mileage just like you're reporting.
 


toby said:
could my trouble be my drive to work is 2 to 3 miles every day?
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yes, turning your engine on and off every 2-3 miles will certainly affect your mileage in a negative way. thats also not all that good for your engine..... you should at least let your engine get all the way up to temp at least once a day (assuming you drive it everyday), otherwise the moisture that gets in your oil overnight never has a chance to burn away.
 
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Jakegday said:
yes, turning your engine on and off every 2-3 miles will certainly affect your mileage in a negative way. thats also not all that good for your engine..... you should at least let your engine get all the way up to temp at least once a day (assuming you drive it everyday), otherwise the moisture that gets in your oil overnight never has a chance to burn away.
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Theres a reason cars with mostly highway miles tend to drive better after a hundred thousand or so.
 
I will get that rpm tomorrow. Is there something i can do for my car because of my 2-3 mile drive to work beside walking to help with mpg thank you
 
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ride a moped? Buy a 80's civic. Short drives like that will kill anything but bullet proof tiny 4 poppers. Try the old slowly run a can of seafoam through your vacuum lines to clean some carbon out trick. Lucas fuel system cleaner maybe, take it out and run the crap out of it once a week maybe
 
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