Low power issues

Thank you for your reply.
Actually I want to explain the issue in detail. I took my car to Toyota Center for routine maintenance at 35,000 Km like engine tune, spark plug cleaning, brake service and O2 sensor cleaning. Then I told them that I have low engine power issue. They suspected that catalytic converter may be chocked and they asked for cleaning. I agreed to clean. Technician at Toyota center remove O2 sensor upstream of catalytic converter and cleaned the cat converter with brush and told me it is cleaned. They showed me the catalytic converted honey comb from O2 sensor port. In my opinion as I seen cat converter was not chocked. Honey comb like structure was alright no sign of fusion or damage visible to me and honey comb color was off white. As I heard from local mechanics that catalytic converter assembly is removed and cleaned the cat converter honey comb with some acid or chemicals. Same thing I asked from Toyota center technician. The technician take car out of garage, removed O2 sensor. Firstly he put some water and then added acid (do not know which acid) in catalytic converter through O2 port without removing Secondary O2 sensor downstream of catalytic converter. After some time he started the car and push accelerator pedal to push the clogging material outside the exhaust. I saw some dark greenish black material coming out of the exhaust after some time that blackish material stopped coming out. Technician said catalytic converter is cleaned now. I starter drive to home after clearing dues. After drive of hardly 2 Km, car suddenly lost power. I was unable to drive my car above 40 km/hr without A/C and 20 Km/hr with A/C at fully pressed accelerator pedal. Moreover there was no check engine light come during this whole drama. I tuned off A/C and kept on driving. After driving approximately 20 km I stopped and switched off my car for thirty minutes. I started my car again and car behaved normal as like before cleaning the converter. Next day I took my car to Toyota center again and I told them the story. I asked them to remove complete exhaust manifold and clean it because I think they push all blackish material to muffler and whole exhaust piping. They washed exhaust manifold with acid and water dark pinkish material came out from exhaust. Further I asked them to perform IT scan because I was afraid that my secondary O2 sensor got damage due to acid. IT scan did not showed any error code. They perform complete cleaning of exhaust manifold and put acid again in catalytic converter this time they removed both of O2 sensors. Engine power did not restored to optimum. Technician asked me to drive the car as it is for two to three days if there is no improvement in power and fuel consumption then bring back your car and they will clean catalytic converter honey comb by cutting the metal housing of cat converter.
Currently my car showed little improvement (without further cleaning) in power and fuel consumption improved from 17 km/l to 19.3 km/l. But before all these issues my car's fuel consumption is 21-23 km/l without A/C and 20-21 km/l with A/C with good power. Although fuel consumption improved but I again felt that car is struggling much more to accelerate with A/C specially. I am confused and do not know what to do? I Pakistan we do not have equipment at home and technicians in official dealership do not bother to do the things you advised. They simply learned to replace the part without diagnosing it properly based on their assessment.
There are no stringent binding of emissions from engine exhaust in Pakistan. Should I remove catalytic converter? Some technicians said by removing catalytic converter check engine light will come and advise to put healthy signal to ECU from secondary O2 sensor by some alteration in software or put some dummy sensor which give healthy reading to ECU. Are these techniques really exists? Should I go for them? Because it is difficult for me to buy new catalytic converter as car is imported from Japan. If I import catalytic converter from Japan, it will cost too much. Suggest me some feasible solution further tell me other reasons for CVT car to lose power.

Thanks and regards.

Dear KHLOW
Thank you for your reply. I hope my vehicle is okay.
Fuel qualities are not good as in Japan and other countries. In Pakistan 54 ppm of Manganese (MMT) is added that is why there are issues with catalytic converter. Moreover in Pakistan N-Methyl Aniline is also used as RON booster without addition of surfactants which could create gum deposition at Inlet valve. When I rub my car's exhaust pipe inside with tissue paper, there is dark brownish color material come out on tissue paper. I do not know what is this brownish material?
Furthermore floor mats proper adjusted. I will check throttle as advised by you. Your opinion regarding tires has worth for consideration. It means car will reading high fuel consumption as distance measured will be less than actual traveled.
But my point is why acceleration beyond 70 Km/hr is difficult for my car. I have to press 80% accelerator or full to increase speed above 80 km/hr. Situation becomes worst with A/C. Moreover I changed my car's tires in March-2018. Changing tires so early will be loss money. Do you think is there any issue with CVT transmission? Do you think, performing cleaning activity of catalytic converter without dismantling exhaust manifold, made my muffler chocked? If there is any issues with CVT transmission then it scan show any error code or not? Please advise what else I should check?

Best regards,
Saleem

Thank you for you kind support.
My previous tires were 165/65/R14 79S and I replaced them with 165/70/R14 81H. Only change of size of 5 mm means this much difference? Moreover car manual Allows this size 165/70 R14 79S. No doubt I felt heaviness when I change tires but little now situation is bad than that feeling. Is speed code change to 81H matters? Previous tires were dunlop current tires are Bridgestone. As I explained in my second reply, After cleaning of my catalytic converter when I drove my car just two km, suddenly my car power dropped and I was not able to speed up my car more than twenty km/hr with A/C and 40 km/hr without A/C. I drove my car with this condition up to twenty kms to next workshop. They do nothing to my car and asked me to go to that workshop where this cleaning was done, When I started my car after twenty minutes my car behave good as before cleaning catalytic converter. What was happened to my car at that time when it was not getting speed above forty km/hr but behaved normal just starting after twenty minutes? When I reached home and started my car again and give some idle throttling then dark blackish material came out from car exhaust, What was that? I did not change my CVT fluid yet, It recommended to change at 40,000 km. Color of current CVT fluid is pink and level is okay. Should I change CVT fluid? Turning on A/C made my car more bulky. Is there any issue with A/C? Please suggest what I should do now? I cannot remove muffler it is welded. I can remove complete exhaust manifold. Should I go for cleaning of exhaust manifold with some chemical or solvent to remove?

Regards,
Saleem

Thank you so much for your guidance!
When my car is not going above forty kph there was no check engine light on. Morover IT scan showed no error codes.
No modification has been done with exhaust system? I am wondering that my exhaust system has got clogged due to feeling of low power that why I want to clean it.
Suggest me How can I check that my car's muffler is clogged or not?

Initially when I changed the tires I felt car bulky but now I feel that car has become more sluggish! Fuel average has been dropped to 17 to 18 kph from 20 to 23 kph? What is the reason for that decrease in fuel consumption average?
Why my car become more sluggish with A/C?
Recommended time for CVT transmission fluid is 40,000 km mileage, current my cars mileage is 37,000 km. Should I change now or wait for 40,000 km mileage?

Regards,
Saleem

This the page of instruction manual where manufacturer guidance regarding tire replacement has been given. If there are such power issues why manufacturer provide an option to tires with that size?

Thank you for you kindness.
I have get it scan of my car for any fault codes. There was fault code of Mass Air Flow sensor as technician described. He reset the fault code and test drive the vehicle. The codes were removed and not popped up again. He said there is no fault code exist now. Both O2 sensors were also okay. Fuel pressure was also okay. Catalytic converter temperature was 590 F before clearing the fault codes and 397 F after clearing fault codes.
I am planning to give these tires to dealer with some depreciation and revert my original OEM tires if he give me reasonable price.
Mechenic told me to inflate little more air pressure to cater increased cobtact with ground.
Today I felt improvement in my car. Will tell you after changing my tires.

Moreover exhaust manifold can be disconnected just after the catalytic converter. I will ask mechanic to do that to check exhaust flow.
Please tell me one more thing, if battery is has worn or have decreased its voltage that could be the reason of low power or any other abnormality?

Furthet I request your assistance regarding another issue.
When I hit bump, crack road or cat eyes below speed of 35 kph, there is vibration like sound from steering side. Sound it like as something vibrate and collide at that speed. There is no vibration in steering wheel when this sound arise. But above forty kph the is no such sound. It has been checked by four mechanics two of them said it is rack assembly issue and front shocks are faulty. One said it is rack and pinion issue. And one said rack ends and ball joints got loose. I am confused who is right. What is your opinion?

Thank you for your kind support
There is no sound on turning vehicle, only sound come when car hits the bump or cat eyes below thirty five km/hr. Sound does not come on every bump sound comes in six occasions out of ten. Which type of video I should make? I can make video sitting inside. I have no arrangement for making video outside or by hanging camera in suspension area.