Dear Members,

My car is Suzuki FX, my car is missing jerking if the speed is blow 40 at 2nd or 3rd gear but once in 3rd gear above 40 no Jerking.

The car is running on CNG only, Allah ka shukar ha no problem in the start up, few weeks back i was facing problem in the morning so i go to mechanic and he tune the car and change plugs, points & condensor and after that starting issue was solve. At that time the mechanic did not adjust the plug gap and plugs were NGK and previously i was using Champion

But the car was jerking so i again went to him and he adjust the CNG and after that car was running smoothly and now after 3 to 4 week again car seems like not running smoothly specially if the speed is below 40.

please advice, what should i do? can i clean the carburator with NASA or clean the plugs or any adjustment in the CNG please advice