Sudden loss of power and blue smoke :(

[BrookWCServices]

Hi all I purchased this van a few weeks ago and may i say i got it cheap, the guy before me had not looked after it at all and it was in a pretty bad way, not body wise, but engine maintenance wise. On the way home the engine management light came on and went into limp mode, now i expected something to go wrong as the alternator was making a horrible grinding sound..Anyway :whistle:, i got home and got my uncle to get the error code, it said it was something to do with the fuel pressure sensor, i took it home and changed the fuel filter which cured it..Great..Had the alternator changed and all was smooth, no noise and no EML`s on, I then started to really like this van till a couple of weeks later. I pulled away from a customers house and there was very low power and blue smoke but then driving for 2 mins cured it..after that though the power was noticably lower but i was working so had to carry on..I checked the air filter the next day..(i should of done this when i bought it i know) illyme: and it was disgusting, replaced it with a new one..fired it up and now the power is even worse??? It makes its mind up when it wants to rev over 2000rpm, so i did some reading and tried disconnecting the MAF plug, now this made it go like a rocket! I thought, well i can use it like this untill a new MAF comes..Next day, turned it on..smoke, uneven idling, wouldnt rev..Turned it off and plugged the MAF in, same..no power but idles perfectly..unplugged it again..more power but not as much as the other day and black smoke!!! Took the MAF off and cleaned it with MAF cleaner..Still nothing..I just cant understand whats going wrong? How could putting a new air filter in make it worse?? Have i done something wrong here?? Could the timing belt need replacing? Could it jumping a tooth cause this?? I dont boast to be a know it all about engines at all, ive just done some reading and made sure i looked before i came on here with this..sorry about the novel but i thought it would save time in replies, any help would be greatly appreciated as i dont want to pay out unnecessarily if its something stupid..

Thanks

[BrookWCServices]

I think my long post has scared people away?? :/

[BrookWCServices]

May i add, the EML is not on and when iam driving, it accelerates slightly more when releasing the throttle?? This van is my lively hood, no van..no cash

[BrookWCServices]

I think i have found the problem..EGR Valve or EGR Solenoid, i have another post on here about a dirty air filter explaining what I found