very low mpg + knocking sound - please help :)

[greesha]

Hello,

Since i bought my car i have constant problems with very low mpg. I do realize its probably my fault but i would like to take everything else out of equation. In last 6 month i have changed thermostat, CTS, spark plugs and MAF. I've cleaned my throttle body. Still no improvement. From last full tank i've done 175 miles (thats actually less than my mate is doing in his 320hp STI).

I do a lot of short trips. I do have a heavy foot.

I've read the codes on vag and all i have there is pressure loss (i've retightened most of the IC pipes yesterday - could be sorted by now)

Im going to visit Tony tomorrow and we are going to do some logging to check how is my car doing before AMD RR day. Only thing i can think of now is Lambda sensor. How can i check if they work properly? Any logging that can be done on vagcom to reveal faults even if no fault code points it to lambda sensors?

PS. I also have a strange *KNOCK* noise coming fron front right of my car when i only feather the gas pedal and release. I dont know how to describe that. When i press gas pedal lightly i can hear knock and when i release gas i can also hear knock as well. It doesnt matter if i turn or not always the same.

Thanks for your help guys.

 

[dippy4000]

I wouldn't worry too much mate, since ive been off sick for the last 9 months most of my trips in the car have been less than 7 miles and i also have a heavy foot (dont boot it till oil hits at least 60 though), mine comes in at approx 170-200miles a tank unless it do a long run then it is around 340.

My car is knocking the same as yours under breaking and pulling away and over bumps at low speeds, My car is in AmD at the moment and was informed that the the top mounts had perished although they were only changed at the end of may.

 

[greesha]

Thanks for the answer dippy. Even when i try to behave properly and i do a long trip all i can get from a full tank is 265 .

That knocking sound must be something different. It doesnt sound as its coming from suspension. More like it's something connected with transmission. I even get that knock on a flat surface.

 

[DannyC87]

Thanks for the answer dippy. Even when i try to behave properly and i do a long trip all i can get from a full tank is 265 .

That knocking sound must be something different. It doesnt sound as its coming from suspension. More like it's something connected with transmission. I even get that knock on a flat surface.

Knocking could be engine mounts; worth checking. Best bet is to log your lambda to check if it is running rich; could just be the short trips and heavy foot tho; mine doesn't do many more miles to a tank than that!