Jerks in third and fourth gear. 70-80 speed regular. This is on CNG, no problem on Petrol. Some thing like "missing" Jerks at pickup too. Get it tuned several times from different places even two 3S suzuki but no improvment. What's the problem? New air filter new NGK spark pulgs.
I try to explain it once again. Start is fine. Will give a litle jerk when apply 2nd gear. When you turn to 3rd and 4th gear at a speed around 70-80, suddenly there are very bad jerks, car jolts like fuel has ended. Then lower the gear or free the accerator for a while and push again then the car will run fine but for some time only (at a speed 100 to 120 there is no problem at all or drive it in 3rd gear up to 90-100 then ther's no probelm).
Its also happens when traveling to some higher place on an even road. Like when I travel to murree this seen(jerks/missing) is continous on the whole road until i convert to petrol.