I have an 3.0 V6, running on LPG. Usually I drive on lpg, but from time to time i do some 50-100km on petrol, in order to prevent petrol injectors from getting choked.
today was one of those days. I was driving around, on petrol. noting extreme, reving to 3000 rpm usually. when i first switched to petrol, i've noticed that the engine became a bit noisier -> when accelerating, there is a periodic louder sound, like one cylinder is missfiring, and in idle is a bit rougher. The sound is something like blown exhaust gasket (i have tought that it is, untill i got new lpg injectors -> from that moment, on lpg, it runs and sounds nice and healthy).
So, i drove around for 10-15 km, and then came home, and while reversing back on the driveway, I have noticed a noticeable amount of smoke coming from exhaust. Car was smoking while under some load, but in idle too. I couldn't see what color was the smoke (it is almost night), but it wasn't black smoke, that's for sure.
My first reaction was A MASSIVE PANIC ATTACK!!! and instinct switching to lpg, after which the smoke stopped in few seconds, and it didn't reappear after i gave it a short drive around.
So, what could cause this?
Could a petrol injector have some residue on it, preventing it from 'closing' completely, and, therefore, enabling a petrol to pour into the manifold all the time, and, thus, creating too rich mixture in that cylinder? I was thinking about this before I noticed the smoke -> too rich mixture will not burn entirely, so it would 'explode' in the exhaust manifold, and create a sound similar to cracked exhaust gasket?
Thanks in advance!