Last week i faced problem on CNG so i went to Hyundai they said tuning will solve this problem, i said ok.
The tuning guy clean spark plugs, air filter, Air control valve, Then he connects the scanner & scanners show several errors the tuning guy resolve all, in last he tuned petrol setting using scanner.
Then all went ok on CNG but when i use the car on petol it jerks out & started giving jhatkas when car drove 15 to 20 km.
Before tuning it was best on petrol?
What might be the cause.