hi everyone,
I bought myself a 2.0l GTI a couple of months back and to start with everything seemed fine. slowly but surely problems started to show their ugly heads.
to start with my revs started to drop slightly on idle, and also started to bounce a little. (i had a quick look at the throttle body and it seems fine) this continued to get worse over the space of a month or so and it is now idling as low as 600 rpm and the engine is stalling quite often.
The engine does not sound healthy at all, and sounds like its running on three cylinders ( chug chug chugging and lots of vibration)
on top of this the fuel consumption has plummeted and i am struggling to get 20 mpg. there is black smoke coming from the exhaust.
thinking it was running on 3 cylinders, i unplugged the leads one at a time. the first three and it died straight away, but when i pulled out the fourth it made no difference, thinking i had solved the problem i changed the plugs and leads. all the plugs were black!
unfortunately this did not fix the problem and it is still sounding and running horrible. going by the black smoke coming from the exhaust and the black spark plugs i have to assume that the engine is running rich.
after doing some research i think that the two most likely causes are a faulty coolant temp sensor, or a faulty lambda sensor. would i be right with my assumption??
my question is... if i unplug each sensor will the ECU go to "defualt mode" and i will notice an improvement in the engine??
i should mention that i put some injection cleaner through it the other day and the mpg seemed to improve a little and the engine sounded slightly heathier.
thanks in advance for your help!!
