Okay so here's a few symptoms that my car is showing but I'm not quite sure where to start looking for the problem. The car had a blown head gasket March this year. My mechanic fixed it (removed the head and sent it in for repairs, and reassemble..etc) . After he was done the car was back and running fantastic again. It drove fine for the first two weeks or so but then I noticed that when I come to a stop light, the car would occasionally stall. The revs would go extremely low and I noticed the revs bumping slightly up & down. This didn't happen before. Now it happens every single day when the engine is warmed up not when it's cold. My mechanic told me my TPS was out of spec but I removed my thottle body myself and re-adjusted it back into spec (it was out a bit) according to the workshop manual. Throttle back in the car...still the same problem. I even upgraded my exhaust to freeflow (my old stock exhaust muffler was rusted and had a big hole in it) - hoping it would improve performance and fuel consumption but still no luck - the fuel economy went worse after this upgrade!! I get like 200km (if I'm lucky) out of a half tank which is equivalent to 124 miles on 8 gallons (not sure if my math is correct here). A friend of mine also suggested to clean my throttle. Does it need some cleaning? Also do you need a new throttle body gasket when removing it? I didn't see a gasket when I removed mine for my TPS adjustment. I should also mention that when accelerating something in my engine bay sounds like an exhaust leak - not loud but just air blowing / hissing kind of sound, the garage that installed my new exhaust checked for leaks on the exhaust 3 times already and they can't find any leaks. I am so frustrated with this issue!!! I use the car on a daily basis. Being a BMW enthusiast, I've started falling in love with this 626!! Any, any advice would be greatly appreciated. Will upload pictures of my ride some other time,,cheers for now!