Let me share the experience I had in AutoMiraj, Angulana (Moratuwa).
I took my car for an engine tuneup. I was using a diesel car and I'm new to petrol engines, so decided to stay with the car and see what's happening, rather than waiting in the comfortable lounge. First at arrival, I asked them whether they clean throttle body and the plugs, they said no and when I try to turn around they said will do that (+ without any additional cost too ).
They struggled to find out where the throttle body of the engine is and with about half an hour they manage to find where it is. Some how they finished cleaning everything, and I gave them new spark plugs to fit. They gave a fuel additive and told me to overdose it as they have seen better results by doing so. Offered me so many expert advises, and made an impression that they the experts.
When I return home, I noticed the engine idle speed is increased. Since my car is an automatic it does not have a tachometer, but I feel the increased engine speed.
Next day morning I took the car to AutoMiraj. They inspected it, had a trial run also, and gave lump of expert opinions. They said as they use some additives engine speed naturally goes up and with time it come back to normal. But I didn't buy these, and insisted on checking with a diagnostic tool. Surprisingly even though they do engine tune-ups they don't have a engine scanner. Since I was stubborn on my stance they took me to AutoMiraj repair shop at Attidiya. Their engine scanner was not working and I was redirected to Pepiliyana AutoMiraj. They do have knowledgeable technician, just when he was told about the idle speed increase he asked is it after a tune-up.
When I dig it up, I found that after any adjustment, cleaning or basically any change of state/condition of the engine and its accessories, a "self learning cycle" in the ECU should be done otherwise the ECU won't recognise the changes made.
This stupid AutoMiraj technicians at Angulana don't know hang of petrol engines, but they do engine tune-ups, and offer the customer loads of "Panditha" advises.
My first advise is avoid this place. (AutoMiraj /Angulana)
Second is don't take these technicians advises without double checking them or having some reliable second-opinion.
As a mechanical engineer I noticed many malpractices during the short time I spent at these places, even in washing bay for an example, they wash the engine bay just after the car arrives but in factory manuals specifically says, never bring cool water to contact with the engine when it is hot, at least 30 mins of cooling should be done before washing the engine.