[NWAGTGUY714]

Good evening all. First post so bare with me.

Just purchased a 2006 Mustang GT with 35k miles in late November and already have an issue. Probably my fault. I was doing about 70-75 on the highway in fifth gear when I dopped it into fourth. Heard a loud pop and the RPMs fell to the floor. Now I feel as though it has lost some power and it flat out sounds like a different vehicle. Is it possible for something to have broken loose under the hood causing air restriction? There is some ticking under the hood and almost sounds like metal vibration when I put my foot into it. Did not throw any codes. The car sounded beautiful before and had a lot more power. I have taken it to Ford who of course could not find anything probably because no codes were thrown and the muffler shop said they hear a slight leak under the hood but the car sounds fine. They suggested possible blown converter. If anyone's has any ideas please let me know. Also looking for good mechanic and shop to get tuning done in the Northwest Arkansas area. Thanks yall.

2006 Mustang GT Deluxe Coupe
Vista Blue w/white stripes
Flowmasters

 

[Bopper]

I'll take a stab at it. You could have blown a spark plug out. The symptom you are feeling is the lack of pressure/firing of one of your plugs. The COP may have contained the blown plug, and what is left is rattling around in there. Look for evidence of fuel leaking from around the plug areas. Obviously this is a complete guess. Good luck.

 

[jpplaw]

Does it sound really muffled? Like the mufflers became like huge cans in a cave? If it does, a converter came apart and plugged up either all the way or partially

 

[NWAGTGUY714]

Thanks gentlemen. I'll have the plugs checked out tomorrow if I can but I haven't smelled any fuel leaking that I'm aware of. I've read the plugs can be most fun to change.

@jpplaw sounds more like what you described. Any guess on cost? Or even how to convince a shop that either one of the problems truly exist without a code being thrown?

 

[jpplaw]

Very expensive to have new factory cats welded in or a whole new H-pipe installed. A little cheaper to have aftermarket cats welded in. But you might be able to find a good used stock take off h-pipe for a decent price from somebody who put headers on.

 

[NWAGTGUY714]

I would like to make sure it is indeed at least one of the cats that is causing this. Only 35k miles..I feel like they should of held up longer. But if that's the case I will probably end up replacing the whole system from the headers on back. Why not. I really do not know at this point. I will probably try another muffler shop or another ford dealership in the area to get another opinion.

 

[JBert]

I would like to make sure it is indeed at least one of the cats that is causing this. . . . .

I guess the only way to make sure it so take them off and look into them or shake them to see if anything falls out

 

[funkboy316]

I would like to make sure it is indeed at least one of the cats that is causing this. Only 35k miles..I feel like they should of held up longer. But if that's the case I will probably end up replacing the whole system from the headers on back. Why not. I really do not know at this point. I will probably try another muffler shop or another ford dealership in the area to get another opinion.

if it is the cats you should check your vin with the dealership to see if you can have it covered under warranty, you may have some time left.

emissions warranty is 8 yrs 80k miles.

that warranty is mandated by the EPA and applies to all vehicles manufactured in or after 1995

 

[NWAGTGUY714]

if it is the cats you should check your vin with the dealership to see if you can have it covered under warranty, you may have some time left.

emissions warranty is 8 yrs 80k miles.

that warranty is mandated by the EPA and applies to all vehicles manufactured in or after 1995

@funkboy316 That had not occurred to me. I'll have to give them a call. Even if it is covered, will they take care of it without the code going off? Noticed you're in SA. Spent the first 26 years of my life there.

@JBert if I had the tools up here I would have already

 

[funkboy316]

@funkboy316 That had not occurred to me. I'll have to give them a call. Even if it is covered, will they take care of it without the code going off? Noticed you're in SA. Spent the first 26 years of my life there.

@JBert if I had the tools up here I would have already

if they do their job properly yes, when they diagnose a car they are suppose to do a thorough analysis not just pull the codes.

IMO though im pretty sure you have something else going on. I think you blew a plug or a coil or something along those lines causing a dead cylinder or loss of compression. but without being there in person its just a shot in the dark.

i just wanted to point out the warranty because most ppl only know about the main bumper to bumper warranties and dont know about the supplemental warranties such as the emissions warranty.

 

[jpplaw]

To me the muffled cave like sound and loss of power is a dead giveaway. Happened to me once, a metallic cat melted, clogged and blew out, leaving only a bit open for the exhaust to get through. Wasn't a cheap cat either, got both replaced for free under warranty from Kooks.

 

[funkboy316]

To me the muffled cave like sound and loss of power is a dead giveaway. Happened to me once, a metallic cat melted, clogged and blew out, leaving only a bit open for the exhaust to get through. Wasn't a cheap cat either, got both replaced for free under warranty from Kooks.

what makes me think its not the cat is the "loud pop and sudden drop in rpm"

like what you said cats usually melt or become"poisoned" which is doesnt make a loud pop

 

[jpplaw]

The stock catalyst material will make a loud pop/crack noise when it breaks and also if the broken pieces forcefully shoot back through the remaining material. The stock Ceramic doesn't melt, it blows apart. The rattling noise is chunks of the material banging around in the pipes or axlebacks. The sudden drop in RPM would be caused by the drastic increase in backpressure in the cylinder bank when the cat clogged. My backpressure increased so much, it actually moved my S/C plenum - luckily I have a stout built motor. As long as there is some catalyst material left in there, you may not throw a rear O2 code.

A blown out or broken plug or COP will definitely throw a code if it affects engine performance to the extent the OP says.

 

[NWAGTGUY714]

if they do their job properly yes, when they diagnose a car they are suppose to do a thorough analysis not just pull the codes.

IMO though im pretty sure you have something else going on. I think you blew a plug or a coil or something along those lines causing a dead cylinder or loss of compression. but without being there in person its just a shot in the dark.

i just wanted to point out the warranty because most ppl only know about the main bumper to bumper warranties and dont know about the supplemental warranties such as the emissions warranty.

I don't know guys. It's just really aggravating that the ford dealership sent me on my merry way. Service advisor said he drag and street raced mustangs and he said he couldn't tell anything was wrong. Actually was surprised by the cars power. I'll give him the benefit of the doubt since the last one he owned was a 2004 cobra. Thanks for yalls continued input. If I have not figured it out by the next time I go to SA I will give you a shout funk. But I do feel it's loss of compression. The metal sound I hear in the cabin seems to be somewhere underneath the cup holders up to in front of the shifter and is very slight with a tight pattern. Now it sounds like it's pushing out air when I start her up. Don't really know how to explain it at this point. Exhaust sounds long on accel and deaccel.

 

[NWAGTGUY714]

Finally got my car looked at by a local shop. The mechanic hooked up the computer to it and he showed me that the cars right bank was dropping out every time I shift gears. Is that the right way of saying that? Only ran thru 3 gears but it was dropping every time on the computer..He pulled the valve cover and checked the cam phaser(which was his best guess as to what the issue was) on that side...nothing. He could not see any sign of teeth slipping or grinding. I guess he had enough. He told me to bring her back once I had a check engine light.
Still feeling a surge of power especially in first and second and more so when the engine is cold. Look like a damn 15 yr old learning to drive. Also , it sounds like quite a bit of air is escaping anytime I start the car regardless if the engine is cold or not. Metal is still banging around somewhere underneath. Getting a tuneup tomorrow if one of the dealerships can get me in. That or Firestone. I doubt this will do the trick but not sure wheat else to do here. Hopefully I can provide an update tomorrow.

 

[NWAGTGUY714]

The stock catalyst material will make a loud pop/crack noise when it breaks and also if the broken pieces forcefully shoot back through the remaining material. The stock Ceramic doesn't melt, it blows apart. The rattling noise is chunks of the material banging around in the pipes or axlebacks. The sudden drop in RPM would be caused by the drastic increase in backpressure in the cylinder bank when the cat clogged. My backpressure increased so much, it actually moved my S/C plenum - luckily I have a stout built motor. As long as there is some catalyst material left in there, you may not throw a rear O2 code.

A blown out or broken plug or COP will definitely throw a code if it affects engine performance to the extent the OP says.

Jpplaw, idk how I missed your reply. What yall are describing makes a lot of since, I just don't know for sure. I'll see if I can't get the mufflers checked out tomorrow depending on where I get the work done.

Thanks for the replies everyone.

 

[luckyloke]

Good luck brother. I all know is I would be loosing my mind on some one if they told me my car was fine. idk how I would keep my cool but more power to you. I know this has got to be beyond frustrating.

 

[NWAGTGUY714]

Lokey, I am losing my mind. Nobody could get me in for a tuneup. Firestone can tomorrow but I thought they were a little steep. Something like $450 just to get the spark plugs changed. Pretty sure they said they were $25-28 a plug and they can't put in plugs I bring. And so it continues.

 

[NWAGTGUY714]

if they do their job properly yes, when they diagnose a car they are suppose to do a thorough analysis not just pull the codes.

IMO though im pretty sure you have something else going on. I think you blew a plug or a coil or something along those lines causing a dead cylinder or loss of compression. but without being there in person its just a shot in the dark.

i just wanted to point out the warranty because most ppl only know about the main bumper to bumper warranties and dont know about the supplemental warranties such as the emissions warranty.

took to a customs shop today. They put it up on a lift and said that the cats were fine.

Going to switch out the plugs this weekend even if I have to do it myself. Anyone know how to test if a coil is bad?

 

[funkboy316]

took to a customs shop today. They put it up on a lift and said that the cats were fine.

Going to switch out the plugs this weekend even if I have to do it myself. Anyone know how to test if a coil is bad?

easy

turn the car on and let it idle

unplug the electrical connector on one coil and listen to the rpms drop and sputter

plug coil back in and move to the next one

if you unplug one and there is no change in idle or rpm fluctuation, that coil is bad.