ok guys, i haven't found anything i'm looking for throughout the thread, so i just need some help and any guidance is helpful. i got my '04 GT in march of 2008, at the time it had about 60k on it. since then i've put more miles on it and i'm at 84,500. my CEL came on about 6 months ago and went to Advanced Auto Parts and did the diagnostic myself and the result was minor gas leak. so i got another OEM gas cap. it was fine until about 2 months ago, then it came back on. i did the same diagnostics test and the same result came up. and since it's still a new cap, i haven't done anything about it.

for the last month and a half or so, every time i get out of my car, there's a burning smell. my assumption is that the honeycomb in the cat is clogged. i was planning on busting it out to get a beefier sound and we don't have strict emissions laws in florida. and now, there's a rattling noise between 2k and 3k rpms. i redline it once a day. if i'm on the interstate i'll redline 3rd to 4th, but if i'm on the road, i'll redline 2nd-3rd. either way, once it hits about 7k there's a tapping sound and i can't figure out where it's coming from.

i'm always a little scared of taking it to Mazda seeing as they like to rape you with prices and other charges, but should i take it in for a compression check? it's still under the 100k warranty.

 

If you are getting the small evap leak code, it could be the gas cap again. I know this sounds stupid but how do you close your gas cap?
I find that turning it slowly and stopping after 3 clicks seals it well and so far I've had no problems with it.

It sounds to me as though your cat is starting to go out. I had an aftermarket cat break up on me and at certain rpm's (especially near redline) I coudl hear this tapping / metallic pinging noise and upon removing the cat I realized it was the broken ceramic honeycomb pieces bouncing around everywhere that caused the noise. (I might have a pic, let me look)

I believe Federal emisison laws cover the Cat to 80,000 miles so you can either gut it out and deal with the smell or go with something like the RP high flow cat which I think sounds GREAT, won't get too much attention from the cops, and you dont' have that wonderful 'catless rotary' smell.

I don't see a need for a compression check unless you're losing a lot of power, your car is stalling, or it idles really rough.

 

yea that sounds exactly what the pinging sounds like. but when i idle you can feel a kick like every 5 seconds. and you can see it on the shift **** when it kicks.

 

how old are your coils?
When my trailing coils weren't firing properly, it felt like the car would sputter / kick every 5-10 seconds while idling.

do you have a timing light? you could clamp the ignition wire at the coils and see if it's firing.

 

actually i just changed them about 300 miles ago, brand spanking new. along with spark plugs

 

it's probably just the cat that's causing the stuttering then.

 

probably, i still have 15,000 to go. once i get to 99k i'll just blow the engine haha

 

ok, so all i need is a jack. i think i'm going to bust out the honeycomb. but if i do that, my CEL will stay on right? b/c of the O2 code? i also heard it will give it a "beefier" sound? and did you have a pic of your cat?

 

how bad does the compression have to be in order for the warranty to constitute a new engine? also i have a warranty for my transmission and when i redline 1st-2nd and 3rd-4th it grinds so i think my syncros are screwed seeing as how i've power shifted a lot over the past year. but if i pay for the compression check and i indeed need a new engine, will mazda reimburse me the money?