Dear All,
I recently purchased a Toyota Corolla 2013 gli 1.6 Automatic. Please let me explain the history for a better understanding 
- When I purchased there there was a rattling kind of noise in the car upon acceleration. I got the catalytic converter cleaned from a renowned shop but the noise was still there. Later it was found that the noise was due to the timing chain tensioner, which went away after replacing it.
- Yesterday I went to a toyota 3s dealer and got the following things done:
(i). Engine oil changed (The last oil grade was not known so I got 10w30 poured into it. Car's mileage is 119k)
(ii). Oil filter changed
(iii). Transmission oil changed alongwith replacement of transmission oil filter and jain.
(iii). Fuel pump serviced
(iv). Throttle cleaned
(v). Spark plugs cleaned
After that I noticed that the engine's performance has become a little lesser, including increased engine noise and lower smoothness. Also when I start the engine I hear tapping kind of noise for a one to two second which goes away after that. Alongwith this noise sometimes the RPM behaves strangely (it doesnot smoothly go upto 1500 on cold start instead goes to around 1100 (seems like its not getting enough fuel or current at this point) then stays there for a very short while, may be a second or less, and then goes upto 1500 before eventually coming back to normal).
Any opinions please?
