This has got to be a fuel problem

Everytime I get off work, I have to travel down a hill, pass the guard house and then get on the main road. Well for about a year now every time I go down that hill and when I stop at the bottom to signal onto the road, the car's rpms will go up and down on my tach. It goes from about 800 to about 200, doing it back and forth. Sometimes, it almost dies on me. Well today, right when It happened, I got out of my car and opened up the hood really fast and a gas smell just started to come from the car. I looked at the engine in around the manifold area especially to see if any fuel was leaking and I didn't see any. But then the gas smell started to go away. So I closed the hood and walked around to the back of the car and sure enough, there was the smell and much stronger. But I didn't see any leaks under the car. So I got back in and when I started to drive off, the car didn't want to go. Then suddenly it went and I squeeked my tires and the car started to bogg back and forth till it started to drive like normal. It was almost like riding a mechanical bull. :)

Well anyways, I drove home and started to look around on what could be the problem. I did take off the gas cap and something funny happened. There was no hisssing sound and the cap came off with no problem. The cap was surely screwed on tight but there was no pressure to fight against. So this makes me wonder, am I losing pressure somewhere or could I really have a fuel leak? Is there something I can replace to fix this? I'm so stumped right now.

How is your gas mileage? Also when you pulled your cap off today, how full was your tank? I would start by checking the seals for your injectors, fuel filter and fuel hoses for cracks.

well my budy had a problem where the exhuast was hitting the gas tank and whore a hole in the corner of the tank. If you have a custom exhuast maybe its hitting the tank and u have a leak. By the way he also had no hiss when he opened the gas cap.

Last time I checked, I got about 39 mpg so that's okay. I looked around the entire manifold area and didn't see any leakage of gas or fluids anywhere. Is there anything that controls the pressure of the fuel on the manifold cause maybe it's leaking a vacuum or the pressure of the fuel. I don't know

Check your fuel pressure and also check regulator. check vacum line to regulator to see of maybe diaphram ripped and vacumm sucking fuel into intake.

Gl

Yeah what jos said. You almost might want to drop the tank, I had a car that the tank was rusted though at the top, so when it was sitting on flat pavment it didnt leak, but when you went up or down a hill it would leak. Also look and see how the seal is on that gas cap - I had another car that the seal on the cap dried out and caused a sensor to read wrong (forget what it was... one of those piss off ones).

Check your fuel pressure and also check regulator. check vacum line to regulator to see of maybe diaphram ripped and vacumm sucking fuel into intake.

Gl
I agree with you Jos The gas tank would not cause a stall.

When you decelerate it causes the highest vacuum in the intake manifold. Thus sucking the gas through a wimpy/leaking inj.

Your fuel pressure reg decreases fuel pressure with manifold vacuum increase. Because the fuel is getting help exiting the inj.

Check your fuel pres reg vac hose is it wet w/gas? Also if you have a means to apply a vacuum to the reg. will it hold pressure. Don't go over 15 in.Hg.

SH