Fuelmonster

My -89 astro 4,3 tbi RWD is a real bigspender on gasoline, on highwaytraffic the fuelconsumtion is near and over 2 litres/10 kilometer it vill be around 11-13 mpg (i think)
I´ve done all that neccessary service & maintanance jobbs,with no positive result on the consumtion
is the oxy sensor something that needs cleaning or change??
can it be something in the TBI unit that fails ??

My local GM workshop can´t give me any help on this topic !!
Chevy:s isn´t the most common brand in my hometown up in Northern Sweden

My wife has a 1994 Astro RWD and a very heavy right foot. I keep track of the fuel consumption for her van and my BMW. Here is a copy of her chart for the few months we have owned it. These are a mix of city/highway driving kilometers.

km litres $/litre L/100km US MPG
505 88.955 0.719 17.6 13.4
586 88.000 0.635 15 15.7
563 88.021 0.699 15.6 15
591 94.000 0.699 15.9 14.8
259 39.966 0.658 15.4 15.2

You need to get the engine checked for fault codes. Maybe a faulty temperature sensor or MAP sensor. Sounds like yours is a little thirsty. These things are pigs. Or maybe you drive in the snow a lot and the tires are spinning!

check from PCV valve in to adapter plate under throttle body.they plug up. backing up "crap" tward the pcv, but most mechinics just check valve. my plate had a vacume port drilled to deep, into this aera,feeding 'pcv' into vacume. poor idle, for 200000 miles,and even a replacement engine ! always diagnosed as vacume leak-cannot locate. then pluged up ,fouled oil rapidly,shows no codes on computer. good luck richard

Make sure that the Engine temprature sensor is reading correctly. If it is reading low, it causes the TBI to inject more fuel.

Ivan