Ok. That explains it. Yes it can be faced at the lathe machine very easily. Just tell the kharadiya to take it easy.
Also, the fuel economy is explained due to exhaust leak before the O2 sensor. It wasn't getting the right readings from a leaking and leaned out exhaust.
I have no idea. He just took it away for a min and came back with it being wet with some liquid. And then fixed it back. What should I use next time to clean it?
o2 sensors are not meant to be messed with/cleaned etc, they operate in a condition in which any harm done to sensor is non-reversable, u can replace it, i guess bad fuel avg cud be caz of that, plz get the car scanned and fuel trims inspected.
I suggest, plz get the car scanned properly and then make exp3nditure accordingly.
How does the car behave? Performance? Any unusual thing noticed? How does exhaust smell when u start it 1st time in morning? Does it smell like paint thinner?
Exhaust pipe condition, csrbon deposits any oily substance?
Any indication that car is running rich? Plugs condition?
Have u tried cleaning the MAF with electric contact cleaner?
How aby cat conv? Any visual inspection made?
How did exhaust manifold got loose? U haf any work done with exhaust?
Car heat up issue?
No oily substance, no smell, no smoke.
Car is performing pretty good actually after the exhasut leak was fixed last week.
it was leaking since a few months (under load) but then the noise got loud a couple of weeks ago ( phut phut phut) thats why i took it for a new gasket last week. He sealed the leak properly with a new gasket ( both left most and right most cylinders were leaking).
then i took a trip to ISB and Peshawar. Performance was great (apart from more fule consumption).
2 days after i came back to Lahore, i heard the leakage again at start up. but it goes away in a couple of mins (i guess when the exhaust warms up)
MAF cleaned a month ago (with throttle body service + new iridium plugs).
No heat up issue ever. as per the exhaust mechanic, cat is fine (but i havent checked in depth myself , since the car performs pretty well for an 11 year old car)
So my guess is a warped (curved) manifold head / face. What do you think?
i have no idea. well but now, i took the positive terminal off for a bit to reset the ECU. and ive been driving the car for 2 days now. I'm not entirely sure yet, but it seems the fuel consumption is almost back to normal. Lets see. still have to get the manifold sorted.
@xenerking @Proverbial_Slang what do you guys think about double gaskets ? 
i want to visit the workshop with pre planned solutions this time. header warp checking and resurfacing is on the list, but i dont want to end up with the same exhaust leak / tick for the third time. Thats why open to suggestions for bomb proof fix !
I wouldn't recommend double gasket as it will require even more careful tightening of manifold bolts.
Ask mechanic to have it "faced" with a facing machine. Not all Kharadiyas have it..
Check all bolts and threads for integrity. Slipping threads could also result in leakage.
I got the exhaust leak fixed for now.
After inspecting the manifold, it was in much better shape than a replacement found from Bilal Gunj. So re-leveled the face, tightened it back with a metal gasket placed. Lets see how long this fix lasts.
how was the inside of exhaust manifold?
carbon built up? thick carbon chunks work as hot spot and get super heated responsible for wrapping of exhaust manifold..
it was a chance to port is nicely from inside used a dermal tool..
