[37mm]

Hey everybody, I'm a newbie to the forums and seeking out your knowledge/opinion to answer my question(s)

I have a 2002 Mustang and I did some basic bolt-ons.

So far: Fenderwell CAI and a Flowmaster dual exhaust system.

This is where the problem starts. Awhile after installing the CAI and new exhaust, the service engine soon light popped on. The car has only 40K miles on it currently, and I've babied this thing since I got it originally back in HS with only 16 miles on it.

Did the light turn on due to the bolt ons? If so, how can I get the light turned off? (it's been eating at me for awhile)

My other problem: I have this really bad rattling coming from the catalytic converters. It gets really bad especially in hot weather. It's not hindering performance of my car, but it's getting really annoying/embarrassing at the intersections. (I have to press on the gas to have the exhaust muffle out the rattling!)

I've been to a few shops, had the O2 sensors replaced. Checked out the EGR valve.

Had some friendly grease monkeys at the local Walts do a full computer check. They tested the EGR valve problem which turned up on the diagnostic and but discovered it was working properly.

They said the rattling is more likely from rocks or I could have banged the biscuit within them.

I have lowered my car and bottomed out a few times. Which could be the reason for the rattling.

Anyway I end my plea for help with a quote from one of the Walts employees: "You've got gremlins in your car".

[GuitarstarX7]

Do your cats have any bad dent marks or anything? On my last car that I had lowered, the cat got crushed and the inside broke into a bunch of pieces and blocked most of the exhaust from flowing.

[QwikSilver07]

if the cats are bad get you a offroad h or x pipe you will proballyy like the sound better lol......

[37mm]

The guy at the Walts shop did mention it looked like I banged the cat. It was odd that the guy thought it wasn't a big deal and blamed it on pebbles getting in.

I was originally there to switch out the cats, have them fabricate an H pipe and converting the Y pipe Flowmasters into a true dual system. Was that a feasible idea?

Do you think the issue with the possible broken biscuit in the cats is causing the service engine soon light?

[Lamonte_1993]

my cats are hollow and they make my service light come on

[37mm]

So, I took the stang back to the shop to check out the rattling once again with a mission of getting rid of the rattling.

They removed the heat shielding on the passenger side to find a good size rock. The other side was dented in (more likely from numerous bottoming out situations in Seattle) So, they're fixing that too.

The Service Engine Soon Light.... that's still a mystery, but my car runs fine and that's an issue I'm gonna have to deal with.

Currently, the car is down the street at the shop, hoisted up getting the cats worked on and receiving a H pipe.

I guess out of this ordeal, I gained an H pipe and minus the rattling.

Thanks for the input to all of you, I really appreciate it. You guys (as always) are the best to turn to.

[Shamrock69]

I had that ANNOYING rattling at red lights....they said it was normal with the 2001 stangs....we have a gravel drive and I had heard it drag a couple times...and I had busted my exhaust...which explained the crazy noise coming from the passenger side in the motor...it started out gradual...and just got worse and worse as the days went on! So I finally got it welded.

Hope everything works out good for u!!