Mondeo engine warning light

[interele]

Does anyone know anything about Mondeos ? My engine warning light came on so
I took it to a garage and the errors were 'System too lean on bank 1' and 'System too
lean on bank 2' The guy reset it and said see what happens. About 10 miles later it
came on again. I took it back and it had the same message ( this now being late
Friday ) he reset it again and we agreed if it went off again I would book it in. So off I drove
and it was a pig, it lurched, at the lights it was bouncing so much and the idle was so
uneven I had to put it in N ( it's automatic ) and had it not been too late to take it back
to the garage I would have done so there and then. Anyway after about 10 miles it
sorted it self out and was OK. Anyway after about 70 miles of driving with one eye
on the warning light I took it to a back road and floored it. The warning light came on
again. Other than it seems a bit feeble at over 3500 reves it drives fine ( 2.5 V6 ) I
was hoping someone could offer some help so I can make intelligent noises when
I take it to the garage

:-)

M

[hughjass]

air leak on the inlet system, usually just a hose.

[interele]

It's booked in on Tuesday. Is there any obvious place I can look for a leak so I can say to the garage 'Should that be like this' When I got it reset they went on about the o2 sensor but I thought the V6 had two and the message is lean on both banks so it would be logical that the fault is something common to both

ta

M

[AlBags]

So it's a V6 ..
Possibly a MAF unit (Mass Air Flow Sensor) I think this model has one.
In the intake pipe to inlet manifold. Expensive units .. look ebay.
Other cars/models use a MAP sensor in inlet manifold.
If it was a permanent problem on one bank, I would check/replace the corresponding Lambda Sensor (same side) in the exhaust downpipe.

[interele]

Many thanks everyone
There was an elbow shaped hose about 8 inches
long that had a hole in it - £70 later no warning light :-)