About 3 months back, the middle "dholki" of exhaust started rattling so i changed it but the replacement was a desi type of dholki as i was in a hurry caz i had to travel to Quetta the next day. Since its change i felt that the engine felt a little heavy and bogs a little if i press the accelerator hard.
On my way to Quetta near Sibbi the car started giving severe jerks on petrol as if engine was shutting down for a second & coming back to life, so i converted to cng and all was fine.
After reaching quetta i felt a severe loss of power while going uphill. So after few diagnostics myself i retarded the timing from distributor & all was fine. no jerks on petrol, no power loss.
but after abt a month which is a week back the problem came back but in a different way. There r mild jerks in driving specially on constant speed as if traveling on an uneven road. The problem persists on CNG as well as Petrol.
The engine now bogs down badly on cng when i press the accelerator too hard at low speeds only. but if i change gears at high rpms then its ok. i have tried tuning the CNG numerous times. Bogging is less on petrol.
Now here is the list of things which i hav already done
1. Plugs changed abt 1 month before the problem started.
2. Plugs r a little sooted but not much.
3. Plug wires checked for resistance but passed.
4. Distributor cleaned.
5. There r no CEL codes.
Question 1: The car was working fine before but after travelling to Quetta i had to retard the timing. thats weird. BTW timing belt change is due & i m planning to do it in a week or so. Can it be a loose or failing timing belt?
Question 2: The "dholki which i replaced was genuine honda & one could see through the center hole to the other side, but the new one was desi & was blocked in the center. Can it be the cause of heavy engine & low pick cause it might b producing more back pressure as it is not allowing free flow.
Also dont forget the constant mild jerks which i m facing now. Your input is required. Specially @Xulfiqar bhai & others.