I m facing unstable rpm problem since 4/5 months. I serviced the carburator from Abdul Rehman carburator splt Tariq Road last December. Drained oil from Cng kit. Rpm drops on petrol as well as on CNG. After draining oil i feel little improvement but not completely. Some time rpm stuck at 1800 then I off the A/C rpm drops. If I drive without AC then it drops more quickly, some time engine shut off. Please help. Input of Zulfiqarabad /capsat is required.