@ all: thank you for ur kind suggestions.
@makniazi: dear i took my car to abid ustad (warsak road),he opened the CNG Kit....but it just workd for CNG... i switch off my car on petrol at night but i still have problems..(i think petrol is not comming generously)
please help me further..... my car have jerks on petrol in first and second gear but drives smooth in 3rd and Top....
i have problem with wat ??? (yesterday i changed air filter as well,but problem is the same)