[Avengence]

stock, shaker 1000

[2006greyGT]

Did ya change the oil? A hiss in the stereo can be caused by anything in the electrical system not connected or grounded correctly.. Mine makes a little more noise when it wants an oil change.... but it doesn't get any less peppy....

[Avengence]

The hiss only happens when the engine is actually running. Weird problems with the volt gauge make me feel like the alt is going bad, thats all.

The less power thing, I could be wrong cause I dont drive it as much since its winter. Also when you reset the battery with a custom tune loaded, it doesnt have to go through a relearn, so it wouldnt feel like most cars do when you reset them right?

[TheUNZippee!]

Typically hissing when the engine running is a ground problem, although it's usually more prevalent with after market systems.

[Avengence]

But I heard that a hiss can be from the alt putting out a bad signal. I just thought it was weird that my volt gauge on the dash was telling me that the car was waay over the high mark some days and normal other days.

[stangracer01gt]

Can you hear the noise inside the car while driving it?

[silverstang]

if the volt meter was way high then your alt. is probly over-charging. I would test it and replace the alternator. I would also do that before you fix the noise. I have had overcharging alternators on 3v cars mess with the VCT in them (makes the phaser do stupid things, and makes some wierd noises), its not likely your concern, but hell anything is worth a shot. Also a "hiss" in the stereo can also very likely be noise from the fuel pump transmitting through the elec. system, which isn't THAT common on newer vehicles but it does happen from time to time.

[Avengence]

Ok cool thanks silverstang. I will check into it. Right now the alt is doing fine and the volt gauge looks normal. I guess I will keep going till it does it again. I think I will replace the battery when I do the alt. All of the sudden, like a month or 2 ago my battery started to corrode on the negative terminal and it has never done that.

[Avengence]

Oh also, I was trying to do a compression test last night and the threads for the spark plug is weird so i wasnt able to hook up the compresson tester to do that. Anyone know where to get the adapter for it?

[BLACJAC]

Originally Posted by Avengence Can anyone tell me what this noise is? Its the louder clunking noise. It doesnt cause an idle change or shake the car. YouTube - Mystery Engine Noise 2005 Mustang GT original post in a diff forum: Ok, new problem... engine clunking? - MustangForums.com

ALL THESE PROBLEMS I READ AT THIS FORUM OR ANYOTHER MUSTANG FORUM , 95% OF THE TIME ITS THE TUNE!!!! i have never ,ever read a problem like ,or similar to this problem with a car that does not have a tune "NO TUNE" its always cars with some kind of tune !!!! i am so glad that i bought the airaid cai , why ??? cause no tune required , or ever shall be a tune , lol

[silverstang]

well, if you want to go fast, you gotta get a tune!!! lol, no offense blacjac, that airaid intake does look clean under the hood of these cars.

to the op, i would research this a little more, maybe even break down and bring it to the dealer, before you go tearing into it.............if your alt. was overcharging at any time, you need to get a new one. Most of the time it only affects the VCT when it is actually acting up, but you never know. I would get some SPR cams from comp while i was at it lol

[radioaction]

Originally Posted by 2006greyGT it can be many things.. most of them not good... were you running it hard before it started? what weight oil are you running? the noise might go away with a thicker oil. it could be cam phaser lash which can be caused by the computer advancing/retarding the timing. It could also be a pulley on the serpentine belt... it it wasn't being beaten then it could be electrical/programing/oil pressure. if it was driven hard just before the problem started then it could be deeper... another way to isolate the noise is take a piece of vacuum line and use it like a stethoscope..

I was going to suggest the same. I've had that happen on our Expedition before (2006 - 5.4L 3-Valve) because of a bad oil change. I usually do them but we were in a time crunch leaving for a trip and took it to a place in town. When we got back the Expy was making that noise. I did some research and found out it was likely the lash adjuster and can be oil pressure related so I decided to do another oil change myself.

I found out that the place that changed it used some knock-off filter that was way smaller than the Motorcraft filters I use AND they had only put 5 qts. of oil in when the 5.4L takes 7. After 7 qts. of Mobile 1 5w-20 and a "Genuine Motorcraft" filter the noise stopped and hasn't returned.

I've not seen this on problem on my Mustang, but apparently it's not all that uncommon on Ford's 3-Valve engines with the variable cam profile.

-Just though I'd share. If you haven't changed your oil in a while you might want to try that as an easy 1st step.

[radioaction]

oops.. double post.

[APER]

Sounds like a lash adjuster. They tick when they are faulty. Ford will replace them there is a bulletin out for it. Again just my opinion...............