I got CNG kit installed in Suzuki Alto VXR 8 months back. Recently i found a problem in my Landirenzo kit. The car runs fine on CNG and petrol both. But the problem comes when it is converted from CNG to Petrol. Initially i press the switch once so that all gas in the line finishes it up but during this, slight petrol is also injected and engine of car doesn't stop, I press it again to fully convert it to petrol. Again when converting from petrol to CNG, it converts normally. But after driving 15 20 kms on CNG, the engine hesitates as if petrol is mixing with CNG. The car looses its pick and i have to stop and park it till the time it gets normal. After that it will go fine throughout till the time it is again converted from petrol to CNG. Is there any leakage in my Petrol line or Petrol shut off valve?? Please guide.