OK hey everybody I have somewhat of a problem my 92 firebird which is a V6 3.1 is just suck down gas like theres a hole in the tank i only get 150 -189 before the needle drop after the warning mark on the gas meter now i got about a month ago 300 -359 to a empty tank ( 1/2 gallon left) and i changed and did everything i could ooo lol and i run a 100 shot NOS kit
Now i changed

1. oil with fiter
2. cap and rotor 2 months ago still good
3. the coil 2 months ago
4. Control Module 2 month ago
5. spark pulgs a week ago
6. the O2 sensor
7. the air temp sensor
8. the spark plug wires
9. added a trans cooler
10. new k&n air filter
11. change the coolant see if i have a blown gasket
12. i cut the cat off a while ago it just rusted to hell

and that about is idk what else to do and my car alway idled choppy between 900 and 450 in park the car act like its going to die and been pops up to 900 again and does this to i put it in drive or reverse. so thank you for looking if u can help i would be very grateful

 

take a flashlight and look down where the bottom of your fuel injectors are, if you see gas there, that could be your fuel leak. you could even take the upper manifold off to get a good look. how old are your injector o-rings? they cost like $2 for a set of 16 so it could be that.
as for the choppy idling, have you tried running seafoam through it? that cured my idling problem.

 

well the idle been like that for 7 years
we i don't smell gas the injectors mmm there about 5 years old had to change them and seafaom idk does that stuff really work

 

make sure the rubber hose going to the map sensor is connected or doesn't have a dry rotted hole in it.

 

Seafoam REALLY works, but prepared for your neighbors to call the Fire Dept, about something burning. The resulting smoke during it is CRAZY!

 

the map sensor .... theres a like hard hose on that one with a rubber boot on both ends its still like new i just tested it for leaks
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-.- i know and i live in a big town and there real *******s about smoke and work on cars in general

idk what else i can change can it be anything to do with the car not getting the right mix of air and gas

 

i had that same millage problem, turned out to be charcoal canister leaking fuel fumes from the tank, mines blocked off and removed now, i get 25mpg, from 10mpg previously

 

how did u block it off

 

ive removed the canister and all asosiated parts, the only problem was the pipe from the tank, but i capped that off like a house gas pipe, everything can be put back together if someone wants to later.

 

look where your hard fuel lines are on your drivers side fender well. trace the one that goes to the charcoal canister. disconnect it from the black rubber hose and screw something in it or cap it off.

 

ok question lol i know theres a line that runs to the throttle body for the Vapor Canister and what do i do with the Vapor Canister Purge Valve that big black disk looking thing so can't i just put the vent form the tank to that so the fumes or gas what ever runs to the throttle body maybe get a .5 of a mile form the fumes lol

 

forget that just block the line/pipe from the tank to the canister, if the canisters bad or you have old pipes the fumes are prolly just pissing out and your fuels just evaporating away. putting the vent from the tank into the throttle wouldnt be good - youl get rid of your vapours quicker and your millage will go down lol

 

-.- god i don't understand this gas mileage **** anyway my and my friend have the same car he runs turbo i run NOS so he adds air i add fuel lolol ok so just check off everything the Purge Valve, the throttle body vac line and the vapor line form the tank