I bought a 1991 turbo a couple of months ago as a non runner and have completely rebuilt the engine with forged pistons, new bearings etc.
After setting the timing and getting it running reasonably well I took it out for a quick spin and it ran quite well with a bit of hesitation. After leaving the car on the drive for a few minutes I went to start it to put it in the garage and it would barely run, stuttering as though it was misfiring and dying if left to idle. The next day it started and ran fine with a slight wobble at idle every so often but nothing too concerning and has been running well like that until today when it was time for its mot. The car started from cold but immediately started running rough and wanting to cut out aswell as smoking. It has now gone back to running well again with the revs at idle occasionally rising and falling.I've got no idea why sometimes the car runs well and sometimes it runs extremely rough and lumpy with no power.
Any help would be greatly appreciated.
Thanks Jack