NA VL, Dual Fuel. When starting on LPG, the system runs fine from cold and warm .. when cold it starts almost instantly, then stalls, then cranks a few times, then starts fine. I'm told this is normal for LPG due to there being some gas left over in the intake manifold, but not pressurised gas in the piping, so it starts, then stalls, then starts again once it starts being pumped again. Warm starts are always instant on gas. Its on petrol that the problems begin. When I first got the car over a yeara go, it was ALWAYS hard to start on petrol .. to the point that it basically couldn't start on petrol when cold, and was a pain to start when warm. Since the head gasket blew and I got a new head (very badly worn valve seats) the car has been able to start on petrol fairly easily when warm (cranks quite a few times before any sign of ignition, but then it starts, idles really low, then picks up and is fine .. and yes, I let the fuel pump pressurize the line). Cold starts are still a problem tho. It will crank away for about 10-15 turns or more, with no sound of ignition happening, then you can hear it splutter a bit, but still not actually fire up, then it will eventually fire .. but the idle will be sooo low its almost stalling .. if I leave it sit like that at idle till the temp guage starts moving, it'll be fine .. as it warms up, the idle smooths out, and then it drives fine .. however, if I try and drive it while its in this really low idle, sometimes it will stall almost immediatly I touch the throttle, and other times it will start to drive, but miss and make banging noises, almost like a small backfire out the exhaust .. again, as soon as it warms up even a little bit, it smooths out and runs fine. So, I'm assuming this must be a temperature sensor? I'm guessing the ECU thinks the engine is warm, and is trying to run it as if its hot .. That would explain the LPG being unaffected, as injection timing is unused on gas. Chances are I'll be taking the car to a mechanic for a total check over soon anyway .. I think there might be some form of blockage in the exhaust too, due to the CAT ****ting itself, so I'll get it all checked out, but is this something I could do myself to change over? How much does a new temp sensor for the ECU cost? (I assume the sensor that drives the ECU is different from the one that drives the cluster, as the temp guage on the dash still seems to work fine ..

sounds like your injectors are dud.

I suspected that to start with too, especially given LPG can foul them, but I wonder why it starts ok when warm, and why it runs ok once its warmed up? And it doesn't have to be a warm start on petrol .. for instance, I can cold start it on LPG, drive it for an hour, then switch to petrol, and it will pick up and drive like a dream .. But I'm not ruling out injectors yet .. Are they by any chance easy to pull out and inspect manually? Unfortunatly I dont have my gregories book with me ..