When I go to put gas in car the gas tank has a lot of pressure in the tank. If I had to guess I would say it hisses for 3-5 sec

sounds like clogged or clogging fuel injectors,sorry for delay in the answer in your problem, been busy w/other issue . suggest easy solution to your problem, purchase lucas fuel injector cleaner,add to your fuel tank. cost $5.00 treats 20 gallons of fuel. just add the ammount that you need. follow the directions on the bottle, you can purchase at auto zone or advance automotive if need be to clear up the sputtering problem. note' there will always be hissing from the gas cap[normal] due to pressure from your fuel pump,it pumps around 180lbs of pressure to the fuel rail that operates your engine the fuel pressure regulator on the fuel rail;regulates the pressure to your injectors, that's what makes your engine run so smoothly.

Check fuel lines that run up side of engine. Lots of times they can chaffe against block and leak. Also be careful when filling car, if you top tank to top of fill neck that puts pressure on lines to canister where canister will fill w/fuel and literally ruin vapor canister.

there is a book publish by the govnt or minister of transport on the exact milage as well if you know how many liters or gallons go in your tank like 80 liters and the gas is 1.00 a liter it cost $80 for 80 liters on a full tank you do 500 km but make sure proper conditions of 100km a hour tires all proper equal pressure the wind is also a facture there is a lot involved to calculate your gas proformance as well if you had a oil change done latly you can find out on a govt site for gas consuption or consumers report

Lots of possibilities.

Could have corrosion build up and rust clogging fuel tank pick up. Usually reverse air pressure helps, but would help to remove tank sending unit to see if you can **** out any water or gunk.

Could have vacuum building up in tank. Make sure charcoal canister purge valve is working right, and no hiss when taking off gas cap.

Could be fuel pump. Check pressure and volume, leakage, etc.

Could be filter. If carb, remember there is a small filter in the carb as well.

If fuel injected, may have bad pressure regulator or safety valve in line.
The pressure test results will help.

Could be a lot of things but i would start with the fuel pump. I would say 9 out of 10 time i get a car that cranks fine but wont start it turns out to be a fuel pump. Have the fuel pressure checked and go from there.

Without actually being able to see it, i can only guess what the hiss is. Have you looked for any broken vacuum lines or anything? The fact that you can tap the pedal and make it go back to normal sounds like a simple throttle linkage problem. Can you see anything that is is catching on?

So, you aren't able to completely fill the tank? If this is the problem, check the vent tube to the gas tank, it's located alongside the fill tube. If it's pinched, bent, or restricted in some way, you will have difficulty putting gas in the truck. The fill tube and vent tube can be replaced as a unit if that's the problem.

If you hear a hissing sound from the gas cap then the o ring that seals the tank is either cracked or tore. the tank has to build up pressure. thats where u r hearing the hissing sound replace it, it should stop after.

Supposed to hiss. There is a pressure sensor on the tank which when bad willl let you know there is a problem. That is why there is usually a warning about fuel spray on the gas cap/lid.

hi before spending your money get the fuel pressure tested then at least you know where your up to it expensive guessing yates210456