Recently I have been encountering this weird noise from my car here's how it happened. Well me and my friend were going to a gun shop go get some stuff right and on the way back I decided to have a little fun and get a speed craving out so at about 75mph I downshift to 4th and take it to about 108mph then let off the gas and gradually slowed bak to 80 car sounded perfectly fine during the period of accleration. but when i returned to his apt building letting off the gas in 2nd or 3rd it sounds like my car is backfiring i can hear this popping noise. From sittin in the car It feels like its right under me like a blew a gasket on the header-cat or cat-exhaust gasket or something. What is this sound. i have tomorrow off and was gonna inspect the above mentioned gasket's but I thought uid get some more opinions. thanks

 

You may be right about the gaskets, but the first thing that comes to my mind is Fowled Plug..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KeithsDAteg &raquo;</TD></TR><TR><TD CLASS="quote">You may be right about the gaskets, but the first thing that comes to my mind is Fowled Plug..</TD></TR></TABLE>

ive been running denso iridiums for less than a year and I rarely drive the car hard if that makes a difference but if others think this I will pull the plugs

 

Cap n rotor may need to be replaced. Try that if you havn't changed it out yet, since its a cheap replacement. If it aint your plugs either, you might have retarded or advanced your timing after WOT. Get a T-gun and check your timing as well.

 

are you sure your cat's not bad?

 

every time one of the racecars afterfire/ backfires its always a header gasket. I would look at that first. I would also pull plugs and check the cap and rotor. It never hurts to look at them and its easy.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 53DC2 &raquo;</TD></TR><TR><TD CLASS="quote">every time one of the racecars afterfire/ backfires its always a header gasket. I would look at that first.</TD></TR></TABLE>

What? You're saying the first thing he should do is pull the head to look at the head gasket? (I'm sure that's not what you meant..)

Check plugs first. Check to see if they all look the same, and are gapped reasonable. If fouled or just worn out, replace 'em.

Also your plugs can tell you a lot about what else is happening inside the motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nightrider &raquo;</TD></TR><TR><TD CLASS="quote">are you sure your cat's not bad?</TD></TR></TABLE>

Ooh, another good thing to check. Could definitely make weird rattly sounds when the guts of it start falling apart.

 

replace spark plugs first

 

cap,rotor, plugs,wires have all been replaced with less than 2 years on them. The cat could be a possibility i have 105,xxx miles on it i dont know what the life expectancy if those typically are but I will check that after i look at all the gaskets.

 

how many miles within 2 years? and its unlikely the cat.. btw, is this with stock exhaust? aftermarket will make that popping sound, or mayabe you have a hole in exhaust but overall it would sound louder if you did.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gsr-2nr &raquo;</TD></TR><TR><TD CLASS="quote"> The cat could be a possibility i have 105,xxx miles on it i dont know what the life expectancy if those typically are but I will check that after i look at all the gaskets.</TD></TR></TABLE>

stock cats should last more than 100k, but sometimes go out before. on the other hand, if you have an aftermarket cat, they probably last only a minimal amount of time depending on the motor setup. for example, carsound cats on a R motor will only see 15k if you're lucky.