Running like a sack of s**t????

hi all really starting to give up now so i need as much advise on what to do as possible

vehicle in question

rrc 3.5 v8 efi

right from the start!

it began to misfire and run very lumpy and even cut out when in drive and come to a stop, also kicking out clouds of black sooty smoke (stinks of fuel)

i have so far changed:

all spark plugs
all ht leads
ignition coil
dizzy cap

still running very lumpy and have had to adjust idel to stop it from cutting out

i have checked all leads are in correct position on dizzy and also carried out a spark test and it is sparking on all 8 cylinders yet still running like crap

what else could it be???? getting low on funds now to sort it and out of ideas what it can be??? as it sounds like she is only running on 4/5 cylinders but she is firing on all 8????

valley gasket?????
air flap meter???

would they cause this???

(JUST TO CLEAR UP IT USED TO RUN ON GAS BEFORE I OWNED IT I HAVE SINCE REMOVED THE LPG SYSTEM)

any help and advise is much appreciated

many thanks in advance

.Sam.

Sound like its running to rich check air filter for start.
the other thing that happens to those engines is the timing chain spockets wear and they jump a tooth and it puts the valve timing out and ignition timing.

Ask Doc Evil he is the master and getting em not running.

Stop!!

You say this is a 3.5, I'm guessing flapper. You say very rich and not idling. Thing 1, disconnect the ninth injector, also called cold start injector - they are a known problem. See if that helps.

Next, check coolant thermistor - use a multimeter to check resistance, search V8 section, plenty info in there. Check throttle potentiometer (with multimeter).

You haven't changed the rotor arm - get one but sure it is a genuine one not a cheap pattern part.

Check mechanical and vac advance are both working and check/set ignition timing.

If you feel happy doing it, remove and clean your plenum and ram housing then check and set the throttle disc (check Haynes) or search V8 section.

See if any of that helps.

Did it run OK before you took off the LPG?

Pete

thank you for replies

i shall go out and get started on it in the morning

and no its was running bad with lpg all connected although i never used the lpg???