I have a 2003 5.4 Supercrew with almost 50,000 miles on it. My questions is this: (I am not very mechanically inclined when it comes to engines so I'm looking for some experienced advise here. Thanks in advance!!)

.....When I give it all its got (meaning pedal to the floor) right when it shifts gears...I hear a "ssssss" sound...as if air was released from somewhere! ANY IDEA what this may be???? This sound only happens right at the very moment the gears shift.

PS: I did take out the "silencer" from the air intake. Dont know if that is related. Also, the truck seems as if it may be lacking some power. No much...but it seems as if.....it could/should have a little more power.

Please help!!

 

thanks for all the replies.

 

Do you have an open air box - with a K&N Filter maybe ?

 

pop the hood and rev it up a few times with your ear by the intake, try to identify it that way. otherwise it could be vacuum somewhere.

 

Mine does that too - It freakin acts like it wants to suck the filter inside out

Freakin thing - I need a Walboro and some 24 lb injectors.

I was running this one , to many seams and it was reduced to meet the TB -




I made another, a solid 3" no reduction - this ones polished inside and has brass ports for the IAC and breather - very high flow ..-

 

you wanna make one for my L intake? lol

 

I prolly could - I have enough plumbing sh^t around here - A farm and fleet went out of business and I was able to purchase there plumbing section about 5 years ago . I still have quite a bit of brass fittings, fernco's and misc - they come in handy

Made a nice manifold for my compressor -

 

How much????

Probably a vaccum huh??? Should I be concerned??

Thanks.

 

I asked if you by chance had an open air box with a K&N filter ? If you do and you removed the silencer - the noise is prolly coming from the filter .

 

Silencer gone! Yes.....however, I only have the drop in K&N air filter. No "open box".....


....the "ssssss" air sound, only happens when the truck is shifting gears. I mean, as soon as the RPMs drop, between gears, its like it is releasing the pressure somewhere and making that sound. ....only for a split second will you hear it.

I wonder if its just the "silencer" I removed. I just hope, I'm not losing any compression or power because of this "sssss" sound.

 

Huh , idunno - you might want to check your plugs - make sure there all tight, just in case.

 

ok well how hard are you listening? you prowling with no radio and trying to keep everything quiet so you can hear that one noise?