Trouble with MOT emissions.

Having trouble getting my 4.0 p38 through the mot because of the emissions. Its a 96, and so far we have changed the air filter, sparks and leads. Is there anything on these that tends to help with this??

a good sevice and some injector cleaner and a decesnt blast before going for the test.Stick some optimax petrol in none of the tescos ****

Oil change helps...

lamber sensers, the list can go on and on. what did mot man tell you..

Is that want to be Lambda sensor?

Right things are getting annoying now....
Still not running right - lumpy on tickover, feels like it is missing.
Runs fine on LPG ALTHOUGH - I think the filler pipe for the LPG has cracked now, as I cant put any in - it just leaks out from under the wheel arch where the filler pipe is.

Is smoking when accelerating hard - only visible when stopped, cant see it when driving.
Really need to get this big lump running right now, any more ideas?

maf senser, would miss on petrol but not on gas..

could it be a dodgy injector? is there any way of testing them?

if yer running lpg present it on that and it shall pass