172 with mid 20s mpg

[bboy]

Hi guys,

My 172 is averaging 25-26 mpg (33 on dashboard). What could be causing this? The car is also very hesitant when its cold and is quite lumpy especially at 30mph in 4th its almost like its losing power for a second. My journeys tend to be about 30 miles and mostly A/B roads. Generally Im lucky to get 220 miles from 3 quarters of a tank. So far iv replaced the post cat lambda sensor and my plugs and leads is there anything else I should consider?.


cheers.

 

[STEVE.M]

Water temp sensor,map sensor,manifold air temp sensor.
Birds nest in the air filter?

 

[bozothenutter]

lambda?

 

[DTM Cars Ltd]

lambda?

Most likely very common needs to go on diagnostic machine with live data to check which one isn't working.

 

[Dan@SJM]

Lambda sensor.

 

[Diagro]

Mines doing the same in regards of fuel but not lumpy.

I replaced the pre cat sensor but still in Same situation.

I suggest you change it though, can be had for 30 on ebay

 

[bboy]

Cheers guys, Just checked my receipt it was the precat sensor I changed the EML is not on but would a diagnostic still show something up without the light on?

 

[bozothenutter]

I checked mine with an obd reader
Check voltages, they should both be about the same