05 TD4 FACELIFT, driving me mad

ok here we go, a little over a year ago I bought a freelander td4 05 facelift, ok it had a few minor issues, but nothing that put me off, about a week later I had it in the garage at work to do a full service, including that little filter on top of the engine, can't remember what it's called but apparently it's the one that doesn't normally get changed. Anyway, while I had all the plastic off I noticed the plug was out on the maf sensor, so I plugged it back in, the car which had previously ran great then ran like a dog, popping and farting totally horrible below about 2k rpm after which it ran great. I disconnected it again and car ran great, well recently I tried it again, same issue, took it to a mate with a foxwell reader and hooked it up, no codes found! I did some digging and found the article about swapping the pressure sensor and lead, this appears to have been done, so I replaced the maf sensor, yes I did buy a cheaper version off ebay, simply because I didn't fancy throwing the best part of a ton away on a genuine one and finding that isn't the issue (been down that route before) and still it runs badly, the symptoms all point to this harness and sensor, but like I said, it appears to have been done. My question is this, assuming it has been done, why was the maf sensor disconnected afterwards, and if the maf was faulty then why is it still playing up with the replacement, yes I know people say the cheap ones don't work, but if they don't work why do they still sell them. I'm being driven demented by this thing now, like I said, without the maf connected it runs fine, it's just I'd like to have it connected, after all, it's there for a reason.
I had a problem last year and fitted a new HP fuel pump, and changed the filter on the LP pump, apart from that it's been a good motor and I like it, but this thing is annoying me now, anyone have any idea's please.

philthespark said:

yes I did buy a cheaper version off ebay, simply because I didn't fancy throwing the best part of a ton away on a genuine one and finding that isn't the issue

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Some cheap MAFs are worse than others, and some TD4s are really fussy about which MAF they have fitted. Only Genuine Bosch MAFs can be guaranteed to work correctly, which is unfortunate. There is an insert available for less than the whole TD4 unit, the insert giving a £20 saving or so.

Nodge68 said:

Some cheap MAFs are worse than others, and some TD4s are really fussy about which MAF they have fitted. Only Genuine Bosch MAFs can be guaranteed to work correctly, which is unfortunate. There is an insert available for less than the whole TD4 unit, the insert giving a £20 saving or so.

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I've been doing a load of reading today and have found an article that stated a sticking turbo will cause a similar issue, so I think it's up on the ramp and drop the turbo, I've read that it's not that difficult to do, and since it's the cheaper option in terms of parts, I'm going to give it a try, been done with that before, spent loads on parts then found out it was something stupid and relatively cheap.