306 1.9 dt

hi there,my 97' 306 1.9dt is lacking power intermittently,sometimes the
turbo works (whistling and power)and other times is sluggish (no whistling
from turbo).is the turbo likely to be knackered or is there something else
it could be.does anyone know of anywhere i could get a reconditioned unit
and roughly how much it would cost as ive been informed that a new one is in
the region of £400.
Also theres a knocking on the back end when going over rough roads and if i
have any passengers in the back seat the mudflaps scrape on the road if i go
over the slightest bump(or road humps)i think it could be the shockers but
id like to know if theres any other reason for doing this.... i would be
greatful for any replys.

 

the knocking sounds like mine did. a sort of light knock which came and
went. never found out what that was.
The power loss, well 've been there too. Changed all the filters and it was
okay. The air filter is the most important one when power is down. Injector
cleaner may help too. When you change the fuel filter refill the chamber
with pure injector cleaner as it will work better than in the fuel tank. Of
course weather condition effect turbos too. Cold air is more dense and so
more power. The 306 intercooler is a poor design being on top of the engine
and so in traffic it soaks up loads of heat and reduces the efficiency of
the intercooler.

Simon