For the past few months, my Civic is giving me this problem that both on petrol/CNG, it doesn't accelerate properly even after applying full pedal. The situation is worst in CNG as I get it tuned from a mechanic but after driving 40-50 kms, it starts missing specially in low gears and eventually dies down and wont start again. I then convert it to the petrol and though it doesn't die down as in the case of CNG, it consumes much more RPM just to get to 100kph.
I have done many things. Tuned the kit, throttle body, tappets etc, also checked the ignition coils but the problem just wont go away. I should mention here that the problem is persisting for the past 2 months. Before that it used to be a charm on both CNG/Petrol and specially CNG.
Is there anyone out there who could help me with this? Any guess? Is there a problem with any of the sensors? Any help will be highly appreciated
P.S. I tried to search the forum before creating this thread but could not get the satisfying answer.