Terrible Gas Mileage...Is this normal???

[unlikely hero]

Just bought this car so I'm pretty unfamilar w/ it. I did a search but nothing seemed to fit my situation. Right now I'm getting like 200 miles to the tank cruising under vacuum not boost. These are my mods:
1990 big rod longblock
arp Hardware
new 2g pistons/rings
balanced crank
balance shafts removed
big 16g turbo
hard pipes
1g bov
clutchmasters stage 3
large intake pipe
full 2.5" AHP custom exaust
avcr and s-afc

The problems I see w/ it right now is that I have a small coolant leak, its idling around 1300, and this is the funny part. I'm running the stock 1g fuel system other than a rewire but my sAFC is set at -8 across. I tried to put the values back at 0 but I would get major bogging. Also i think my sAFC maybe isn't wired correctly because I don't get a reading under airflow unless w/ the 6bolt swap there is no airflow reading. Well anyhow I just want to know if this is normal gas mileage or if not were I should start to look in fixing it. Thanks
=Jason-

 

[Tallen]

Maybe its tuned to rich, or maybe theres a Walbro 255 hiding in the gas tank.

 

[unlikely hero]

Would a rewire pump put as much as a 255? I don't think its a 255 cause wouldn't be pretty loud?
=Jason-

 

[DJ23GSX]

My gas milage is about the same but i have a couple more mods and i have a walbro 255 and its pretty loud definatly a lot louder than stock. Have you checked for any intake leaks?

 

[unlikely hero]

Havn't had time yet, funny idle started up now it will climb up to like 2000 then drop to 1000, climb and drop over and over. Trying to find a place to start in fixing it.
=Jason-

 

[DJ23GSX]

aahh the famous idle surge. My talon did that and i couldn't fix it for the life of me. Most people block off the egr valve on the intake and this gets rid of it. I didnt try this but many people have sucess with it. A friend of mine had a bad intake manifold gasket and his idle surged like that he fixed the gasket and it was all better and i do remember him saying that his gas milage was a little better after that too. hhhmm I think an itake test should be your first step.