Low mpg xantia

[Goran]

Hi, i have low mpg problem with my xantia 1.8 8v (101bhp) for some time now. I get around 19 mpg on lpg. Similar consumption when i drive on petrol just bit better mpg. Changed the spark plugs recently, air filter is quite new also. Need some advice for what are the main suspects that can affect the low mpg.

[Timmo]

Air flow meter? Guessing that it is running okay other than shocking mpg? 19mpg from a 1.8 is good going!

[daviemck2006]

Thought my tct was bad at 25mpg [emoji15] [emoji23]

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[CitroJim]

Check your brakes aren't binding, the tracking is correct and tyres are both correct spec. and properly inflated...

Just a little brake binding will make a big hole in fuel economy...

[xantia_v6]

I don't think that the 1.8 has a MAF. But the Lambda (Oxygen) sensor is a likely suspect.

[RichardW]

Or coolant temperature sensor.... Needs Lexia to see if anything looks out of kilter.

[Goran]

Thanks for the tips
@Timmo yes car is running fine. It used to run around 24 mpg, and i was happy with that. Just from reading some other posts i figured that this 1.8 8v engine is thirsty to run, but am complaining because i had better mpg...
@CitroJim brakes are ok recently checked
Can ecu or MAP sensor be the problem in this situation? Some cracked vacum lines maybe?
If anyone has more ideas am all ears

[CitroJim]

Can ecu or MAP sensor be the problem in this situation? Some cracked vacum lines maybe?

Yes, the MAP sensor and/or the vacuum line to it can cause the issue, as can an air leak anywhere downwind of the throttle butterfly.

In my experience if there is a problem with the MAP sensor and/or the vacuum to it the engine will run poorly, especially at idle... As it will if there is an air leak.

Often you can hear an air leak as a hissing noise on idle...

You really need to get a Lexia on it to see what is going on, especially the output from the Oxygen Sensor...