make sure the engine is in correct tune, valve timing and clearances too, also make sure the distributor is good, its centrifugal advance should be overhauled and make sure the vacuum advance is good, if you have swapped for an EFI type distro with twin port vacuum advance remove it and buy a NEW original vacuum pod, (it used to be Rs 1400/- 12 years ago).
The carburettor vacuum pipes should be correct and idle speed with trans in D should be 850 rpm with or without A/C, the A/C solenoid setting should be only to compensate back to idle speed not increase it. - Make sure you actually have an Accord A18 carburettor, most have been changed to civic 1.2 and 1.5 ones which choke the engine as its throats are very small.
Make sure the secondary throttle works when required.
btw your fuel consumption can only be afforded to 100 kms/tank at best - no more than that, the car is heavy, its geared tall - no helping it out.
if you adjust your engine correct - it should sound very rorty - most mechanics may tell you the main and big end bearings are bad, they are not, thats how the engine should sound - and the best power comes on near 2500-3500 rpm - thats where the long manifold breathes best..
Make sure the engine gets to normal temperature otherwise the intake manifold may cool down to the point of condensing the petrol back to liquid droplets - its also bad for CNG too as cold CNG is heavier. Always use genuine paper air filters for this engine and make sure you have the cold intake pipe installed - its the rubber pipe that connects the air filter to the fender which causes the engine to suck cold outside air.