Just an up date on this,
first, exactly what i said ,DID happen,cleaned ECU terminals, put car back together,ran it around,then left it running ALL morning-no probs.Rang customer to tell them,then 1/2 hr before she turns up,you guessed it ,same prob again! Back to the drawing board.
Mike- I spoke too soon after your post without really thinking.Apologys, but 25 yrs in the business and i did'nt know that the system in this little polo was able to shut down a single injector! That's one of the many disadvantages of being a sole trader,in that you only find out these things the hard way or by few and far between (and expensive) courses.
Now,i've not done any more checking/testing since the above as i got involved with something else as i waited for customer to collect. But thinking along different lines now, i suspect that this is exactly what is happening to injector no 1.Why else would all 4 cyls come back immediately the fault code cleared?
Sean and Lee-now basics is what i like!
No mention of any coolant /water loss or overheating and all the plugs look good so for now i shall put head gasket to one side, when the prob is NOT there it seems to idle/run fine.
I need to go back Monday and concentrate on how it runs before (i'm assuming) no 1 injector has shut down.
I'll start with compressions and gas test (could be an air leak?)
The pressure's on now as the first thing she'll say is "you've had it a week!"
Cheers
Colin.