OK I had posted this in the 'Tech' forum but it was suggested that I move it here.
AS OF LAST NIGHT THE QUESTION WAS:
"I have just reconnected the loose connector on the sensor just after the air filter (Mass Air Flow?). Fiat Multipla 1.9 JTD - Bosch EDC15C7 CF3/EOBD Diesel Injection.

I have run the Multiecuscan software and the only oddity that I can see is:
* Intake Air Quantitiy 46.4 mg/l
* Desired Intake Air Quantitiy 367.6 mg/l
Is this a real difference between what should be happening and what is, or am I not understanding what it is trying to tell me?


I have looked at other threads and probably need to check the MAP sensor and also the intercooler hoses."

MODIFIED QUESTION AS OF NOW:
OK last night it seemed to rev OK on the drive but I tried to drive to the station this morning.

It accellerated slllooooowwwwly up to 20mph (I'm on the dual cw at this point). Pulled over, unplugged the ~$£#@$ MAF and drove fairly normally to the station. I have just ordered a replacement MAF (just the sensor) from eBay for £25.

Before I reconnected the MAF it was belching smoke on start and had poor accelleration but did run OK generally once warmed up.

I'm still keen to check the MAP and intercooler hoses so does anyone have pics showing where the MAP and Intercooler hoses are under the bonnet?


Cheers,
Steve

Could show a marea JTD for reference..

It's looks as though the MAF is dirty. Have you tried cleaning it? With the MAF disconnected, the ECU falls back to a 'safe' setting which is why your performance is then restored to some extent. It'll be fine like that for now that unless we get extreme (hot or cold) weather.

The low reading you're getting from the MAF is probably because the element inside has some dirt on it. The MAF has an element inside (usually a very thin wire or metal film) which has a current passing through it. Air passing over the element cools it, affecting its electrical resistance. This resistance is what the ECU monitors and from it works out how much air is flowing through the MAF, tempered by another sensor elsewhere which tells the ECU what the ambient air temperature is. The dirt insulates the element and so stops the electrical resistance staying in line with what the ECU mapping is expecting. It knows roughly how much air should be coming in because it's monitoring the number of lungfuls of air the pistons are pulling in at a given RPM. Dirt-insulated element = higher element temperature = ECU thinking there's low air flow. Then your fuelling goes to pot.....

Don't be surprised if the cheapo ebay MAF doesn't fix it, or if it does, not for very long.

Reluctance to pick up revs and power tailing off on long uphill climbs are classic symptoms of a dirty MAF. MAP sensor and vacuum tubing faults usually become apparent under full throttle in 3rd or 4th at around 3,000rpm. I'd avoid playing around with those bits until you're absolutely certain the MAF isn't at fault.