I'm interested in any advice/experience anyone might have about fueling
problems with MPi Coopers.

I have a '99 Cooper with a S works upgrade.  At the start of March, it
spectacularly failed its MOT on high emissions, with CO up in the 4% range
(pass is <0.3%)and high HC levels.

Test centre said 'nothing we can do mate, its an engine management issue,
you'll need to speak to Rover..........Oh God, I said....Anything but that.

Anyway, it is now the 22nd April and I have had:

1, New coolant temperature sensor
2, New Cat
(admitidly both broked, the latter by a massive aberdeen council speed hump)
- Still failed
3, New ECU
- Still failed
4, Another new ECU
- Still failed, worse than before
5, Reset of timing chain pulley to check timing (at behest of JCG)
- Still failed.
6, Specialist inspection/tweaking by MG/Rover 'Engineer' (Travelled up
specially)

To give Rover their due (and the Mechanic who has been working on my car)
they have not charged me for any of the work post CAT replacement (which
must run into hundreds on manhours alone)  and have been spending a lot of
time on the phone to John Cooper Garages who don't know whats wrong with it
either.......After some bad experiences with Rover in the past, this time
they actually seem to be giving a damn.

They have replaced or substituted every sensor and connection in the engine
management system and nothing makes any difference.  They can't find
anything wrong mechanically with the engine either!!

Current theory (from Rover engineer) is that the ECU has got 'confused' and
they need to force some of the parameters to make it fuel correctly.  This
is apparently a fault with the firmware? and needs Rover to work on a patch
which is unlikely considering they don't make the car anymore and there
aren't that many on the roads.

Has anyone had this problem with their MPi (of any flavour)????

My only alternatives seem to be:
1, stick with it
2, replace the ECU with a non programmable aftermarket system
3, replace the entire engine management system with something like a webber
alpha and accept that the car will need specialist treatment for the rest of
it's natural life.

I'm getting to the point where this is actually funny as I can't get cross
about it any more.  If they were goofing off, I'd go barmy but the poor
mechanic is tearing his hair out.

Am I flogging a dead duck here?

Desperately,

James