Recently my engine has started to be unresponsive when driving away (from cold).

It's only from dead cold (e.g. first drive of the day).

It's almost like the throttle is disconnected and I just get pulled along on the cold start RPM to about 10mph.

After a couple of hundred yards, it goes back to normal. I recall it happening last year in the cold weather briefly too.

If i start it up from cold and don't do anything, it'll run for a minute or so, then hunt a bit, maybe another minute, then run normally.

I can't see it being mechanical, I did a pretty comprehensive overhaul during lockdown 1, including new cam, lifters etc. There's no fuel/oil/water cross contamination.
During the overhaul, I cleaned the idle air controller, intakes, etc etc. Maf is OK. Coils, plugs and leads all new.

This is running on petrol, not LPG (takes about 5 mins to get warm enough for the LPG to switch over).

Nanocom shows P0172, P0175, P0134 but has done since I owned the car, which i put down to the LPG conversion upsetting the numbers...

Any ideas?

Cheers

The codes may have something to do with it. On a cold start the fuelling will be open loop initially to give time for the lambda sensors to heat up and start giving an output. It could be that the mixture is so far out that it doesn't want to run right. Have you tried resetting the adaptive values?

Might be different these days but I had an omega on log and when it was hard to start/ lumpy running I had to undo gas feed to injectors and spray carb cleaner in it then reconnect and fire it up ----- something about gas causing wax build up ----- set up I had was zavoll But that 8yrs+ ago

@Richard, not recently. i did after the overhaul. I'll give it a go and see what happens when I have chance to do a run for it to learn again.

As Symes says' it could also be LPG leaking into the manifold so you have a very rich mixture when initially started. Try switching to petrol for the last half mile of the journey to use up any remaining LPG in the system.

I've also had a very intermittent occurrence with mine where it would start as normal but not want to rev. After 20 or 30 seconds it would clear and run normally or if I switched off and restarted it would run normally too. I put that down to the purge valve sticking open and flooding the manifold with petrol vapour. As said though, it only did it very occasionally and hasn't done it now for a couple of years.

will try the LPG last 1/2 mile test.

Your latest message sounds like mine. Will try turn off and on again.

Where's the purge valve?

Dunno on a Thor, on a GEMS it's on top of the LH shock mount. It's got a hose from the charcoal canister and another to the inlet manifold.

Just a random thought could the MAF need a clean or ICV sticking (dirty)