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I've got a problem with my 98 civic, d14z2 with LPG. It takes 5 or 6 seconds of cranking to start after I drive it and leave it resting half an hour or more. But if I leave it resting loger, like for 24 hours it starts right up, no problem. If I turn it off after it cranks and starts, the second start is normal and starts right up. So only after sitting between 1 and 24 hours it cranks long. I changed the fuel filter, spark plugs and the coil, distributor and else was changed 2 years ago. Tries to turn the key off and on 3 or 4 times to make the fuel pump pump mores gas but it's the same problem. I've god a cel for rich/lean mixture and for secondary o2 sensor. Does anyone know how to fix this issue?

 
Rep Power: 222

No clue about lpg cars unfortunately. My guess would have been fuel pump. Maybe a temp sensor that isn't reading correctly?