My 87' rx7 has trouble receiving gasoline, the gas will pump every couple seconds then stop, its like there is not enough pressure for the flap to open up, any suggestions? Also I don't think its supposed to have air rushing out of the tank when I open up the gas cap, any suggestions on that too? Thank you.

 

Push the nozzle past flap?
It’s common to vent when removing the cap, the less gas in tank the more prolonged the vent. It’s just equalizing the vacuum developed as the tank level went down.

 

Interesting theory Sgtblue, but the tank pressure should always be above ambient pressure, never below. There is a one-way check-valve (vent) that allows fresh air in to prevent vacuum due to the dropping fuel level. The cap will allow some pressure to build though typically due to vapor thermal expansion. The fuel vapors displaced by the incoming fuel during fill-up have to return out the gas pump fill nozzle. If the nozzle shuts-off automatically, the gas station pump vent is the problem, not your car.

 

That’s also interesting. Almost every vehicle I’ve owned has vented when the cap is removed, the amount inversely related to the level in the tank. And it sure seems to be vacuum, not pressure. I always thought the check-valves were to minimize leakage in a roll-over or from collision, and the vacuum that developed naturally wasn’t enough to overcome them.
But I admit I’ve never studied the system as you apparently have. Still, unless it’s very different from the FD, I’m pretty sure the pump nozzle inserts past the “flap”. And I’m not familiar with any “pump vent” system. If air can’t escape the tank as the fuel goes in, then the nozzle will shut off. So if the nozzle is inserted properly and it still shuts off, then my first suspect would be the venting system on the car, not a pump issue. And that should be easy enough to determine by changing pumps or gas stations.

 

just tossing this out there, if slow to refill is part of the symptom...

could be this TSB
Category Applicable Model/s Subject Bulletin No. 028/87
4 1986-1987 RX-7 FUEL TANK FILLER PIPE HOSE Issued 7/3/87

DESCRIPTION

If you encounter a 1986-87 RX-7 that is difficult to fuel or takes a long time to fill with fuel, the problem may be due to a collapsed or improperly installed filler pipe hose. If so, replace the filler pipe hose according to the repair procedure shown below.

......

NOTE:
Install the filler pipe hose on the filler pipe so that the overlap length is approximately 50 mm (2 in).
PARTS INFORMATION PART NUMBER DESCRIPTION FB01 42 240D Filler Pipe Hose