1vryfststang

Well I finally got to do a full tune up this past weekend on my 99 Stang. As I was under the car I finally had the opportunity to see just how the exhaust was ran. When I bought the car I was told it had an upgraded exhaust....but the previous owner had no idea what kinda of setup since he didn't have the work done. Plus my Service Engine light was on and reading O2 sensors so I was really anxious. This is what I found out.......coming down from the manifolds it ran into2 cats the from the cats made a x pipe then to 2 dual Flowmasters...... the setup looks all bolt on....but I am not sure about the cats? that is kinda were I am confused and the x pipe was that aftermaket as well? Thanks Everyone!

35thAnni99GT

If it was stock you would see 2 big collectors/cats on the bend, then another two afterwards. Most aftermarket companies that make catted midpipes use 2 cats so I would say you have a brand X aftermarket x-pipe.

1vryfststang

Ok GOOD....do you have any idea why that my o2 sensors would be bad since it is aftermarket from flow?

98MustangGT46

+1. Also some companies will have there name on it of the cats somewhere. Also stock it would be a h-pipe.

redass02gt

o2 sensors can go bad on their own. I would reset the idiot light and see what happens.

LOOT

I had some O2 sensor problems a while back. Go to autozone and have them run a codecheck and it will tell you which one it is.Ifthe problem is in the ones after the cats your car will still run fine but if it's in the ones before the cats nearest to the manifold your car will run like crap. It affects the air fuel ratio and all that. If it turns out you do need a new o2 sensor please make sure you spendmore and get the real oem ford ones. I tried running those Bosch ones from autozone and they were junk. My car ran like crap and the check engine light would not go out. I tried several of them and all the same. Finally I got a tip from a guy. Take your bad o2 sensor out and hold it with a pair of vice grips. Heat the thing up with a torch until it glows red. Get it good and hot and then immediately while it's red hot dunk it in a cup of water. It will break all the carbon and junk loose. It fixed mine. Yours may be a different case but it's sure worth a shot.