gti 8v agg running rich

[Beenie]

hey guys my 8v is running fine but not perfect.

is starts first time every time, doesn't misfire and is smooth with it.

but

its smells rich from the exhaust
recently it's been using more fuel, I understand its cold out but I'm struggling to average 30mpg
I checked the timing the other day and the plugs were very black

so whats up with it? I've been reading other posts about lambda and coolant temp sensors but I replaced my cat and lambda sensor about may last year when it failed on emissions.
I've checked for fault codes with a bosch kts unit and it comes back all clear.

any suggestions?

[Christo77]

Hi there..

Start doing some searches on here and reading relevant posts..you'll soon see all the common things to look out for..

Back to basics though first..what about the air filter!  condition/changed with servicing etc..?

Next thing on my list would be to clean the throttle body internal, there's other things to check but plenty of reading will get you clued up about your prob and plenty more as a bonus.

[Wayne]

Temp sender faulty is very common.

[Khare]

As wayne said, the temp sender is the most common one.

Other things to look out for is a faulty MAF, corroded earths and blocked air filter.


Start off with air filter, get a new temp sender and then renew the plugs, NGK are good and cheap. If it still runs rich then I'd sway towards MAF.