I have a MY98 Impreza Turbo UK.
Yesturday morning it started missfiring it just about ticks over but not all the time and its puffing out black smoke. Can some one give me any pointers as to what it could be as i am fairly new to imprezas.

Thanks

 

sounds to me like a leak, do you have a front mount?
I would check all boost hoses regardless as its bleedin rich and this indicates that air is not getting through the system.

 

No i dont have a front mount. The garage have just phoned to tell me no faults have come up on diagnostics, they are saying it could be the turbo but im not to sure how well they know these cars any more help would be great.
Thanks for the pointers peanuts.

 

Sounds like a plug has gone down, a lead or the coil pack.

You could take each lead off 1 at a time (WITH THE ENGINE OFF) and start to see if it is that.

 

The problem is not there all the time. When i took it to the garage last night it was missing a bit to begin with but was then fine.

 

Update from the garage. Spark plugs were shot had a 5 mm gap in them would this course the black smoke?

 

Yes it could!

 

LOL @ 5mm gap!

 

plugs did not have a 5mm gap in them.

 

just was going on what i wastold by the garage. Got the car back last night all wasfine running really well untili drove it home tonight. To begin with the boost was really jurky accelerating from 40mph in 4th then it picked up then as soon as i went into 5th it started to miss fire again, when ipulled over the revs dropedright down to the point of cutting out then it started hunting from 0 reves to about 1000, it done this for a bit then just cut out. left it forabout 5 mins started it back up and it was ticking over normally but really lumpy to drive. Need some help please

 

MAF sensor?
when the engine is running you can disconnect the maf sensor, if the car cuts out then it can be presumed the maf is ok. if when disconnected the car runs still then it can be presumed its goosed.
Next up, o2/Lambda sensor, same trick with the disconnect.

Both sensors are easily accessed and the wiring is just a small clip about 4 inches back from the sensor so easy to do.
Try a search for MAF sensor and Lambda sensor and do a bit of reading, but for God's sake lay off the boost as you are potentially into fried engine territory.
HTH

 

I would also suggest you put less trust in the garage from here on in and consider a scooby specialist.

 

Cheers for that Peanuts i only went to the garage as it was a friend of a friend. Im not using the car at the moment and wont use it until its fixed. The strange thing is it was started this morning and ran perfect no coughing or spluttering.

Thanks Simon

 

Does yours have a purple labelled MAF and is there an induction kit fitted?

 

Yeah it has a purple maf. No it has the standard filter on it