Took The Stang to the Shop Today

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do you still have cats on the car w/ that exhaust? is it running ok other than the smell?

Hey Pete,

Yes i do actually, when I took it in they said that the cats were fine, but yeah other then the smell and the misfire at WOT it seems to be running fine still gets between 22-24 MPG on the highway, but im thinking if the plugs and pack do not fix it, i might have to invest in a new xpipe with cats..
 
im suprised that most of the 'techs' here haven't told you to look into a new x or h pipe first. Rotten egg smell is almost always related to cat issues. Theres no real way to check them. But if the material inside gets broken/clogged it will definantly produce the smell and could cause driveability issues. I'm sure i'll piss a lot of people off with this post, but all im saying is that before you throw away money at expensive parts like coils and mafs, start simple. (theres always a lot of over-diagnosis around here and especially at dealers). A basic tune up with plugs,fuel filter as mentioned could certainly fix the WOT issue, and in my opinion there is a clear difference between the smell of a car running rich and a car with a bad cat/cats.
 
im suprised that most of the 'techs' here haven't told you to look into a new x or h pipe first. Rotten egg smell is almost always related to cat issues. Theres no real way to check them. But if the material inside gets broken/clogged it will definantly produce the smell and could cause driveability issues. I'm sure i'll piss a lot of people off with this post, but all im saying is that before you throw away money at expensive parts like coils and mafs, start simple. (theres always a lot of over-diagnosis around here and especially at dealers). A basic tune up with plugs,fuel filter as mentioned could certainly fix the WOT issue, and in my opinion there is a clear difference between the smell of a car running rich and a car with a bad cat/cats.

+1

I agree with you on many points. However, the reason I as a "tech" havent recommended or advised replacing the midpipe is I am not there to accurately diagnose the condition. At minimum he is probably looking at 150 for an o/r pipe, and much more for catted. There were also no codes mentioned for catalyst innefficiency. And actually there is a way to check cats...you need to monitor the readings in OBD II data list before and after the cat.

There is alot of over diagnosis around here, yes. And honestly its always the same thing when it comes to driveability issues...everyone runs around sayin clean this and replace that.

Note clogged cats could also cause his WOT issue. If its bad enough, the exhuast back pressure will keep too much exhaust gas in the cylinders (less fresh air/fuel that can enter), and the burn wont be as good.
 
Well it looks like the H-Pipe might be the problem after all, as the new Accel COP and NGK tr55 gapped .054 went into the car yesterday. When we pulled the orginal COP off, there was one that look a little burnt and 1 were the boot was cracked. Also there was an issue with only one plug being loose all the others had white center caps, no real carbon build up, if need be i still have the old plugs if you would like me to post some pictures if that would help at all, otherwise looked good from what I could tell. But I took the car to work today and got on it a little bit and it could still smell the rotten egg type smell. So the steps that have been taken to this point are new COP's and Plugs, cleaned my air filter and MAF sensor. The car is still not throwing any codes nor is there any drivability issues, normal driving the car runs like its brand new, no missing, hesitating etc. just when getting on the highway and the intial burst of throttle throws off the smell and it only lasts for a couple of minutes at most then disapears and crusing speeds. I still get between 22-24 MPG on the highway with the car and around 16-18 in the city. which if i would look at my window sticker is pretty normal. So i am looking at either getting just getting the SLP xpipe with cats and match them up with the stock headers, or just finishing it and getting the bassani midlength and xpipe with cats aslong as it will fit on an auto.. Any more thoughts?
 
Not to revive an old thread without a true purpose, but I felt there was a need for some final clarification required.

Anytime you got WOT your car will fatten up which will produce a "smell" from the cats burning off the raw HC's.

Any catalytic car that goes WOT past you, take a sniff, you will smell the HC's being burned off in the cat. It's normal.
 
Not to revive an old thread without a true purpose, but I felt there was a need for some final clarification required.

Anytime you got WOT your car will fatten up which will produce a "smell" from the cats burning off the raw HC's.

Any catalytic car that goes WOT past you, take a sniff, you will smell the HC's being burned off in the cat. It's normal.


I figured that was part of it, I guess i was a little concerned as it was happening even taking off from stop lights and etc and a medium throttle. But it appears that cleaning the filter, and changing the plugs and COPs helped a little, I will change the fuel filter when i get it out to see if that changes anything.. but otherwise it seems to be ok for the time being. The strange gargling sound that I heard was actually coming from the throttle body as we think its a bad gasket.