when i take off my gas cap there is no pressure behind it

Is there a particular reason why this causes you concern?

isnt there supposed to be? im getting crap for gas mileage it idles fine in park then in drive it fluctuates drive to a stop light it idles fine then go to another it fluctuates again 87 4wd wagon 2 barrel 

and if i dont let it run for 5 minutes or so it loses power when i start driving

The fuel tank is vented into the charcoal canister, so no tank pressure should build up.  Sometimes, with an almost empty tank, you can get a slight vacuum in the tank.

 

My first impression from your description is a clogged fuel filter.  This usually presents as idling ok, but loss of power when demanding more from the engine.  (High speed, accelerating.)

 

You did not mention any smoke issues, or smell of fuel from the exhaust or sooty tailpipe/bumper area, so I am guessing that the engine isn't dying from a stuck choke or other too-rich condition.

nah no smoke or anything ive changed the fuel filters but not the charcoal canister is there away to determine if that is defective a do smell gas coming from under the hood but not from the canister more around the carb area. there looks to be a silver filter on my lines under the car around the fuel pump was is that i can get a pic if needed

Charcoal canister should be a non-issue.  It is the big black plastic object with 3 or 4 small hoses running to it in the engine compartment near the radiator electric fan.

 

Where was/were the fuel filter(s) that you replaced?  IIRC, the object near the driver's strut tower is just a vapor separator.  (All of my EA82s are FI, so are a little different.)

 

Have you looked at your sparkplugs to see if they are sooty or gray or white?  If not yet, it is useful to know whether things are too rich or too lean.

the fuel filters i replaced one is in the rear and one is in the front attached to carb i will check the plugs out also it dies if i take the top of to the air box 

You need some people with better carb experience to join in.

This sounds like a vaccume leak somewhere to me, it could be in the evap system. Do you smell gas in the car?

some times yes 

A thought to check:  Are the screws holding the top section of the carb to the body of the carb loose?  (Not a totally random thought.  The airbox cover removal prompted this Q.)

 

some times yes

There is a plastic tank in the rear passenger wheel well that could be cracked, this might cause a vaccume leak and would explain your symptoms.

Edited May 4, 201312 yr by mikaleda

The diaphragm in the valve on the charcoal canister does go bad over time, which will cause a pesky vacuum leak that is often overlooked.  

 

When was the last time your carb was rebuilt?

The diaphragm in the valve on the charcoal canister does go bad over time, which will cause a pesky vacuum leak that is often overlooked.  

 

When was the last time your carb was rebuilt?

im pretty sure its the same one i just bought it its an hittachi 

  whats this 

That is a fuel pulse diaphragm, compensates for the pulses from the fuel pump.

That is a fuel pulse diaphragm, compensates for the pulses from the fuel pump.

im gonna replace all the vacuum hoses and will make a new topic if it continues also that charcoal canister is like 160 bucks at parts geek 

I've got a charcoal canister if you want it p.m. Me and I'll send it to you for the price of shipping.

im gonna replace all the vacuum hoses and will make a new topic if it continues also that charcoal canister is like 160 bucks at parts geek 

I replaced mine with one from a '91 Jeep Grand Wagoneer.  They're $30 at Rockauto.  If you search around you can probably find others that are closer in size to the subie canister for $30-$50.

im pretty sure its the same one i just bought it its an hittachi 

Not quite sure what you mean by this.  Do you mean it's the original carb and you just bought the car?  Or do you mean you just bought another carb?  My question was about when the carb was rebuilt last.  If it's hasn't been rebuilt to your knowledge, then that might be in order.

Not quite sure what you mean by this.  Do you mean it's the original carb and you just bought the car?  Or do you mean you just bought another carb?  My question was about when the carb was rebuilt last.  If it's hasn't been rebuilt to your knowledge, then that might be in order.

yeah i just bought the car it was kept up though only 113k on it when i got but i dont know what has been done to it i bought it from an older couple they bought it auction just to drive a couple of times it set for 3 years while they had it 

yeah i just bought the car it was kept up though only 113k on it when i got but i dont know what has been done to it i bought it from an older couple they bought it auction just to drive a couple of times it set for 3 years while they had it 

The gaskets are probably dry-rotted and a lot of the fasteners could be loose.  The float is probably out of spec too.  I would recommend a carb rebuild.  The kits are ~$30 and a rebuild isn't really that hard to do if you follow the directions step-by-step.  If you are ok spending some money, a Weber swap is a good investment, especially if your car only has 113k.

The gaskets are probably dry-rotted and a lot of the fasteners could be loose.  The float is probably out of spec too.  I would recommend a carb rebuild.  The kits are ~$30 and a rebuild isn't really that hard to do if you follow the directions step-by-step.  If you are ok spending some money, a Weber swap is a good investment, especially if your car only has 113k.

all the webers i found wont fit if equipped with power steering