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Old jetta-MPG steadily getting worse - Nellyspania
When I got my old VW Jetta MKII I was getting average 40 MPG (usually 20 mile round trips) but this has slowly started to drop over the past 3 months and is now about 30 MPG with a 'chokey' smell coming from the exhuast. Also the plugs are sooty. It has a new air filter in but is still bad. The autochoke unit works OK i think, it opens back up after a couple of minutes after start up. Is it a problem with the carb?
Old jetta-MPG steadily getting worse - Adam Going (Tune-Up)
Carb is favourite, but could be many other things as well. Distributor vacuum unit is very important for mpg, but wouldn't usually make the exhaust smell rich. Blocked crankcase breather, dirty air filter due to exhaust maionifold leaks, carb icing due to inoperative hot air intake system, and fuel pump diaphragm leaking into crankcase also possible.

No disrespect, but if you are not too mechanically minded it would be worth getting a professional diagnosis. Ask friends & family for a recommend, or look in Yellow Pages under "Car Engine Tuning".

Regards, Adam
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