Can anyone think of anything that might be causing MAP sensors to fail on one of these??(other than that they come in distinctive blue/yellow boxes )

It has gone through three (Four if you include the original OEM one!)over the last few weeks!

Now,to be fair, I cannot confirm that the "original" was actually faulty, the customer had already replaced it on the advise of another bcause the engine was running like poo. When that failed to cure the problem I was called in and discovererd that the head gasket had blown but on completling the work I found that it still ran badly and I discovererd that the MAP output was "Stuck" at 1.7 volts. The customer got his own replacement under warrently which worked fine for a couple of days before the MIL came on again and it ran badly. I discovererd that this time the output was "stuck" at 0v.

I got a replacement which again worked OK for a couple of days but, last night however, I got a call saying that it had (apparantly) failed again (MIL on, running badly). I will not be seeing the car for a couple of days (Van repairs! At 260,000 miles its entitled )

when I fitted my one I checked the socket to ensure that there was no voltage on the signal wire (Like a short to 12 v say) and it ran fine for 4 days!

So that is three (assuming that the most recent failure IS the map and not something else) failures in a row! I have had this with "Blue/yellow Boxes" before (Corsa coil packs! You end up doubting your diagnosis after a while )

Now the question is, are these failures down to dodgy replacement parts that are being made in a back room in Shizwan Province somewhere for 25c each? Or could there be somehing on the car that is damaging them??