Hi, i'm new to the forum but seeked help over Google when eventually becoming fed up of the strange problem my Fiesta seems to be having. The car is a 1.25 ltr Encore 1997 model and has only developed the problem within the last month. The problem seems to be that whenever i accelerate by pressing down the gas pedal the car seems to make an audible hissing sound, almost like air is escaping or being sucked into the car.

The sound seems to originate from the rear left of the car, where the fuel cap is. I've already tried driving around shortly with the cap off to see if the seal was somehow causing the noise and have also recently changed both the oil and air filter, but still the noise seems to occur. I'm not quite sure if there is a large performance decrease, i'm averaging about 330 miles to a £35 tank of petrol. I'm only a 17 year old new driver with little, but increasing, knowledge of cars (however my step dad and best mate are both fluent). The strange thing is that when revving at a stand still, no hissing or sucking sound can be heard, but when moving even in first or second gear it occurs. However, when i shift into 5th and lightly tap the pedal the sound disapears so it is definitley related to the revvs.

Finally, it does seem like the sound can be heard from outside, almost over the engine sound, and sounds ALMOST like a turbo whistle but all the time.

Any ideas?

Thanks =)

Hi, i'm new to the forum but seeked help over Google when eventually becoming fed up of the strange problem my Fiesta seems to be having. The car is a 1.25 ltr Encore 1997 model and has only developed the problem within the last month. The problem seems to be that whenever i accelerate by pressing down the gas pedal the car seems to make an audible hissing sound, almost like air is escaping or being sucked into the car.

The sound seems to originate from the rear left of the car, where the fuel cap is. I've already tried driving around shortly with the cap off to see if the seal was somehow causing the noise and have also recently changed both the oil and air filter, but still the noise seems to occur. I'm not quite sure if there is a large performance decrease, i'm averaging about 330 miles to a £35 tank of petrol. I'm only a 17 year old new driver with little, but increasing, knowledge of cars (however my step dad and best mate are both fluent). The strange thing is that when revving at a stand still, no hissing or sucking sound can be heard, but when moving even in first or second gear it occurs. However, when i shift into 5th and lightly tap the pedal the sound disapears so it is definitley related to the revvs.

Finally, it does seem like the sound can be heard from outside, almost over the engine sound, and sounds ALMOST like a turbo whistle but all the time.

Any ideas?

Thanks =)

Could it be a hole in the exhaust? Mine had a hissing noise and then one day it sounded like one of those corsas the kids drive around my local morrisons car park.

Could it be a hole in the exhaust? Mine had a hissing noise and then one day it sounded like one of those corsas the kids drive around my local morrisons car park.

Hmmm i thought that, but upon revving the engine loudly in neutral you can hear it.... At first i thought it was the exhaust but my step dad thinks differently... It sounds almost like a turbo being put on when accelerating, would it be pretty obvious to notice a hole in the exhaust?

Thanks =)

Hmmm i thought that, but upon revving the engine loudly in neutral you can hear it.... At first i thought it was the exhaust but my step dad thinks differently... It sounds almost like a turbo being put on when accelerating, would it be pretty obvious to notice a hole in the exhaust?

Thanks =)

When I had a hole in my exhaust I thought it sounded like water gushing. Infact, I used to sit at traffic lights making the noise happen because it sounded strange.

Then it went bertung.

Hmmm i thought that, but upon revving the engine loudly in neutral you can hear it.... At first i thought it was the exhaust but my step dad thinks differently... It sounds almost like a turbo being put on when accelerating, would it be pretty obvious to notice a hole in the exhaust?

Thanks =)

Only a suggestion but have a quick look at the exhaust, what your looking for is small black sooty patches on the exhaust indicating a tiny perforation. If you find any it "could" indicate you`ve a perforated exhaust. ( holes aren't necessarily obvious as exhausts normally start to perforate first )Again it depends where your hearing this sound from? ie. if you hear it from the engine compartment try looking at the exhaust downpipe near the bottom or around the manifold area. if you hear it from outside the car try looking underneath.

Re-check all your Air Filter connections, it sounds like you're 'sucking' air in, a bit like having a K&N Induction kit.

is the noise located round the fuel socket or the engine bay ?

Could it be a hole in the exhaust? Mine had a hissing noise and then one day it sounded like one of those corsas the kids drive around my local morrisons car park.

Yeah, I remember getting that. I blew a hole in my exhaust when I pulled away from a red light way to strongly. Blew a hole in the exhaust and, to be honest, it sounded amazing. But it was all sorted within a day.