Assalam-o-alikum!
Dear friends it is first time that i have purchased a car, it is mehran vxr 2009 with company fitted cng, but initially there was a problem that sometimes it was missing so much like it is not getting current, so i went to electrician and he told me to change the coil (which for automatic valves) which is fitted on the cng regulator, now that issue has been resolved and from that day there is a new unique problem that after a little driving if i turn off the car and if i start after 3 to 5 minutes then it is not started on cng but then i start it on petrol then it is easily started and then i convert it on cng then every thing goes fine, and this problem is only if i start the car after 3 to 5 minutes, but if i start the car within 1 30 seconds of turning it off it starts normally, and also if i start after 1 hour or half hour since it was turned off then it is again normal, so the problem is only between 3 to 5 minutes, here no mechanic is able to solve the problem kindly help me.