Ford Focus 2001 Help Please...

Hi all, I have just joined this site so a big hello from me...

I have an old Ford Focus 1.8 Y reg shed... but I love this shed it gets me
from A to B perfectly ... I have started having a few issues with it and was
wondering if anybody could tell me the possible diagnostics before I take it to
an over charged and rated garage :(

Firstly it is LPG converted, I got the kind gentleman at the local garage to
fill the LPG up as I’m not confident enough to do this... sounds silly i know!
.. Whilst he was filing up he asked me to turn my ignition on (not turn over)
so I could let him know how full it was: / ... I done this and it stayed on the
red bar indicating no gas was present... after a few trips in my car my gas
gauge came back to normal but still refused to work on gas.... until recently
but then flickers off when it wants to... any advice on that first

Secondly my car has started to take a while starting in the morning or even
when hot it doesn’t fire up like I used to takes a few seconds, also when I
drive the first few revs drop out on me and loses power so to speak.. Until I
hit 2000 revs plus...

Thirdly my left wheel makes a knocking sound when I turn corners or
roundabouts etc... Like a clunk noise I’m no mechanic but I thought it could be
wheel bearing or something?

I know this is long and boring with loads of spelling mistakes! I just want
my baby running how she should and back to normal... also the engine smells
like its overheating when I drive it as I get out the car but the temperature
on dash is fine... and plenty of water in car suggestions or advice would be
grately apreciated :)

Thank youuuuuuu =]

I forgot to mention when i drive the car now the revs stay really high for a while when i put my foot on the clutch to change gear?