I have a Renault Clio 1.4 16v 72kw from 2003. I have this strange problem where when the car has been idling for some time (when in traffic for example) and gets more warm (temperature indicator more than half way. This means it's > 90 C right?) it wil start to misfire when it's running on LPG. If I let it Idle for too long it will eventually stall. When I start to drive at higher speeds again and the engine cools from the resulting air flow it will run perfectly again (also runs good on idle again)(temperature indicator just below half way now). The engine runs well at higher RPMs on LPG even when it's warm from idling.
Note: -On petrol I have no problems at all. -The radiator fan will eventually come on when I let it idle so there is no problem with that. -I have expensive NGK Iridium spark plugs which are supposedly better for LPG. They've had about 50.000km. -I still had the old filter when this started happening.
Now I have already been doing some research and one thing that is very likely is that the injector rail is clogged. This is very likely because I replaced the dry filter waaay to late (it did 100.000km lol) because I didn't know it needed replacement. However, I really doubt this is the problem because the car runs fine when not getting warm from idling to much. I wonder why would The injector rail start to behave differently when the temperature of the engine becomes higher? (during idle) It's not welded to the engine block although it's near it. So yeah it shouldn't get that much hotter right? It might to idk.
So my guess it's either spark plugs or the injector rail. The problem is that i'm not sure because:
1.The spark plugs work fine with any temp on gasoline and lower temps with LPG. 2.The injector rail works fine with lower temps and why would it start failing with higher temps? shouldn't it start to work better lol?
Btw I have this LPG system (dutch): https://agit-lpg.nl/portal/files/2014/09/Eurogas-Folder-Evo-360-NL.pdf
Should be the same as this (english): https://landirenzo.com/sites/default/files/upload/impianti/evo-lpg.pdf
So what I'd like to hear is: What should I try first, plugs or rail and if that doesn't work what else could it be?
Thanks for helping out.