Poor MPG on mk2

I have noticed lately that my car is doing awful MPG.....and it is shown by the MFA in car that it is now doing 16.8 mpg! instead of what i normally get which is 35 on average. any ideas on how this can be resolved? running rich perhaps?

the sensors may be playing up????

Fitzy wrote:

the sensors may be playing up????

could be! i had my 8v GTi do a good MPG started getting poor, so i gave it a good service, plugs, leads FUEL filter, and cleaned the throttle body where the butterflies are cos it had quite alot of carbon built up, air filter the lot. started getting 43.7 MPG!

give the throttle body a clean out with carb cleaner!

And clean the idle stabiliser valve as well, that also can be a problem.
Check if the crankcase breather on the top of the engine is split, it will make a hissing noise if it is.

i would say its some find of vacum leak

or everyone says that it is usually realted to the lambda sensor if cleaning the tb doesnt provide results then you should try replacing the lambda definately

Or you could always not pay any attention to your lying MFA?

One question i've always been meaning to ask that. Why do all you mk2 drivers pay so much attention to IT??????????

IT is an old computer that does lie, and not that accurate.

Old car, dirty sensors, not idle situations. Come on people, Why?

HAHA fair comment bazza

it's just that fact. even i have noticed the fuel needle is running low much quicker. just checked the mfa and it was lower than normal. Will try these ideas though. cheers guys.

Bazza wrote:

One question i've always been meaning to ask that. Why do all you mk2 drivers pay so much attention to IT??????????

IT is an old computer that does lie, and not that accurate.

Old car, dirty sensors, not idle situations. Come on people, Why?

i loved the mfa on my old vr6............play the mpg game!!........how low can u go!!!

so ur tellin me bazza that with ur diesel, u wouldnt be SLIGHTLY curious about what mpg it MIGHT be doin!????

i got 8mpg on a run down the galleria dual cariageway and ive only got a 2.0 that must have been fun in the vr....

Fitzy wrote:

Bazza wrote:

One question i've always been meaning to ask that. Why do all you mk2 drivers pay so much attention to IT??????????

IT is an old computer that does lie, and not that accurate.

Old car, dirty sensors, not idle situations. Come on people, Why?

i loved the mfa on my old vr6............play the mpg game!!........how low can u go!!!

so ur tellin me bazza that with ur diesel, u wouldnt be SLIGHTLY curious about what mpg it MIGHT be doin!????

If it dipped below 460miles per 3/4 of a tank, then i'll be concerned

Not got MFA on the diesel, even VW knew that it would kick petrol car ass, MPG wise anyway

hahahahahha................good answer!

9/10 blocked or partially blocked breather (in rocker cover)
1/10 you got a leak

when you have been driving for a while and you put your foot down (usaully on motorways)does it feel like you are driving into a strong head wind ?
have you got any oil leaks ?
the block gets pressured and cant release it hence the poor mpg and performance

or i could be talking crap again

I think ur right John. Yeah it does feel like driving into head wind! exactly.

And yeah i do have an slight oil leak - this due to the pressure build up?

Where do i find the blocked breather then?

Three or 4 sensors on the side of the block, one controls ISV, and the others....... do something else (not sure on the valvers!) change the lot of them.
Also change all your vaccuum pipes for new. Costs a couple of quid a metre, so do the lot as even a slight leak can cause grief.
Get some carb cleaner and clean out the ISV & throttle body too.