yp its the 99 Park ave, I did pull the cover and see NO signs of a leak. It will go for a week then the CEL comes on and it spits out about 1/4 cup of gas and when you remove the gas cap it lets a ton of pressure out.

Then it will be ok for another week. I replaced the cap too. Its a plastic tank and doesnt leak even when full to the top, only when the pressure is way up and the CEL comes on. This time it had about 1/4 tank when it did it

Maybe it'* anorexic? lol I know wrong disease...

We should look this up in an fsm or online ... hey. Check the code at Gearchatter.com They have the FSM'* online.

sorry, I have no idea how to do that or what an fsm is ?? Any advise ? Someone said its a fuel vent valve but I dont even see that listed, and the info I read on the purge valve doesnt sound like it would cause this problem.

Thank you

I do not see a fuel tank vent listed for your car. You need to check the connection at the pressure sensor on the tank. Check for any damage to the sensor wires, Check for an open in the 5 volt reference A circuit to the fuel tank pressure sensor harness connector. Don't recall which wire that is, just check for 5v between ground and the terminals. If you have 5v and find no open wires, replace the pressure sensor.

shouldnt the cap vent the tank ???

A little bit, but not enough. Now go check the tank pressure sensor and wiring.

Everyone who has stepped into this thread wants to see you get things fixed, but you have to do your part. When given info on what to check, you need to do the check and come back here and tell us whether or not your were successful. If not successful, then we try another avenue and we keep going until the problem is solved.

A FSM is Factory Service Manual. They are expensive, but you can find them on-line as reference material at such sites as www.gearchatter.com as Bill suggested.

I would suggest that you pick up a Haynes or Chilton manual at your local auto parts store to give you some basic reference material and they will help you learn more about your car.

Take a picture of the top of the pump. I'm thinking it'* the standard three hose plus two electrical connections.

One of the three hoses is a vent tube that runs to the evap soleniod up front.

The pressure sensor is simply a pressure sensing sensor that doesn't vent, only monitors pressure. aka the one telling you there'* a problem.

can you tell us DTC code it always helps then you know wher to start looking

Emission Hose Routing (VIN K)




(1)To Vacuum Brake Booster(2)To Accessory(3)To EVAP Canister(4)Throttle Body(5)Fuel Pressure Regulator(6)EVAP Canister Purge Solenoid Valve(7)EVAP Service Port(PCV Valve(9)Intake Manifold


EVAP Control System Overview




(1)EVAP Vent Valve/Solenoid(2)EVAP Vent Valve/Solenoid Ignition Feed Circuit Terminal(3)EVAP Vent Valve/Solenoid Control Circuit Terminal(4)EVAP Vent Valve/Solenoid Filter(5)EVAP Vapor Lines(6)Fuel Tank Pressure Sensor(7)Fuel Tank Pressure Sensor Ground Circuit Terminal(Fuel Tank Pressure Sensor Signal Circuit Terminal(9)Fuel Tank Pressure Sensor Circuit 5 Volt Reference Circuit Terminal(10)Fuel Filler Pipe(11)Check Valve (Spitback)(12)Modular Fuel Sender Assembly(13)Fuel Limiter Vent Valve (FLVV)(14)Pressure/Vacuum Relief Valve (Optional)(15)EVAP Canister(16)EVAP Canister Purge Valve/Solenoid Ignition Feed Circuit Terminal(17)EVAP Canister Purge Valve/Solenoid Control Circuit Terminal(1Intake Manifold Vacuum Source(19)EVAP Canister Purge Valve/Solenoid(20)EVAP Service Port


Once you have the code that is stored in the pcm read, we have more information we can provide. There is an evap system which if functioning properly should keep any pressure from happening in the fuel tank.

Holy fuel pump Batman. Ok this stuff is over my head sorry. The top of the tank has like 3 lines and 2 of them have a hose on them and one is just a nipple. The electrical connections look fine. If you can offer a little guidance of how to check the voltage I would appreciate, if not thats ok too.

It seems to be a problem when the tank is like 1/4 full. The it will be fine for a week or so then on comes the CEL and the pressure is back . The cannister is under and forward of the fuel tank and I removed the cannoster and it was not full of gas and the lines all blew clear. I appreciate any help here but again some of this is over my head but with details I could do it