Engine 'missing' when hot?

[Rogbik]

1.9 Petrol/LPG DG engine,
Runs fine on choke but after about an hour 50/60 miles is feeling (sounding) as if its missing,
changed the plugs today, 3 plugs were a sooty black (looked like the were running a tad rich)
plug for No 2 cylinder looked as if it had been running at the correct temp (it was a brownish black)
Have been running on 4*+ petrol rather than LPG, when running on LPG engine stalls when stopping at junctions.
Got a new set of leads on order.
Had a full service about 1000 miles ago, no signs of any oil/air leaks etc,
Anything else I should be looking at please?

[kevtherev]

who fitted the lpg?

[Rogbik]

who fitted the lpg?

Not sure without digging out the paperwork, but its been ok for the last 6 years.

[kevtherev]

who fitted the lpg?

Not sure without digging out the paperwork, but its been ok for the last 6 years.

Ah a nugget of untold information!
if the lpg was ok before your troubles started I would suggest it's carb related

Is the autochoke flap working correctly?
Are there any air leaks? (vac lines, gaskets, servo hose etc)
does the lpg petrol cut off solenoid work ok

I feel if you take this to your lpg installer the petrol side of it will get fixed

[Rogbik]

who fitted the lpg?

Not sure without digging out the paperwork, but its been ok for the last 6 years.

Ah a nugget of untold information!
if the lpg was ok before your troubles started I would suggest it's carb related

Is the autochoke flap working correctly?
Are there any air leaks? (vac lines, gaskets, servo hose etc)
does the lpg petrol cut off solenoid work ok

I feel if you take this to your lpg installer the petrol side of it will get fixed

Cheers Kev,
I'm stuck at work for a week now so can't do much,
I have a new set of leads to fit when i get home,
if that does not improve things I will change the air pipes.
Its about time I had the LPG serviced so I will let them check the carb/solenoid
Cheers

Roger.

Roger.