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Thread: Z18XE very low mpg

  
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    Z18XE very low mpg

    Hi people i'm looking for some help please! i have a 2001 astra sxi. it is doing around 20 mpg when knocking around, surely this is not right?!
    I have tried a full service, new therostat which was needed as it was stuck open, i also removed throttle body and thourghly cleaned. none of these have made any difference.
    Could this have anything at all to do with the lamda (or oxygen) sensors. when i monitor them with opcom the 1st sensor is permanently changing voltages very quickly (from 50mv to 900mv) but the 2nd sensor more or less stays the same. is this right?
    I am left scratching my head here really haven't got a clue but surely this low mpg is not right is it?

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    Are there any holes in the exhaust?

    The reason I ask is a guy was talking to me today about exhausts, and he said that having a hole in the backbox causes more fuel consumption
    But by the sounds of it you've found ur problem
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    yes your lambdas are running correct, the first one will constantly switch in response to the varying fuel/air ratios and the second one will remain fairly static if the first one is doing it's job correctly, which yours is. My mates 1.8 sri only used to do about 25 mpg when running around town and in the low 30 mpg when on long runs.

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    Mark T's Avatar
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    Short runs around town will kill economy.

    My wife's CDX runs about 33 mpg on my work run (25 miles on fast b roads)
    It's reading 26 mpg at the moment, around town shopping and school run.
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    thanx for your opinions guys. so it seems that i just need to accept the car is crap for fuel economy!
    thanx again!

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    if you are going to just drive around town, get a prius.
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