Hello, I have santro 2004. The car runs fine on CNG but on petrol it misses and hesitates, most noticeably when engine is cold, in first and second gears. I have got the injectors ultrasonically cleaned, fuel pump and filter replaced, throttle body, IACV and intake manifold cleaned, tappets adjusted but the issue persists. I got the car OBD scanned and no issues were found. I suspect it some sensor might not working properly and causing this issue. i have checked TPS with voltmeter and its producing 0.46v at closed position and something like 4.4v on wide open throttle. Seems its working properly. On checking MAP sensor output i have found that when the ignition is at ON position there are 3.9 v output. When the car is idling the MAP sensor voltage fluctuates between 1.6 - 1.65 volts. One interesting this thing i have observed that when i accelerate the car the voltage fluctuates between 1.6-1.9 volts which seems a little suspicious to me. Can some experts please advise if this is normal output for a MAP sensor or what else could be wrong with the car?

Asif