Just recently my car started backfiring alot when it's cold. I can rev it up to 1500rpm and it will backfire atleast once when I let off, sometimes it does 2-3 times! It will also periodically do it after it's warmed up.
The car doesn't pull near as hard as it used to either and really drops off after 6k rpm.

Boost is the same. My air/fuel ratio seems normal. You can tell the car isn't as peppy but it's not bad until I get on it. Got new plugs (stock NGK) a couple of weeks ago and wires(NGK) are only a year old.

Only thing I can think of is maybe a weak/bad coil but the old plugs looked normal. This is my only car!

Any suggestions? Previous experiences?

 

I dont have any idea on what the problem could be but i know a RX7 mechanic in Florida who might be able to give you some feedback. He is a friend of mine and you find him on AOL Instant Messager. HE is really nice and im pretty sure he will be happy to help you.
his AOL AIM name is: renegaderacin

Good luck
Saul V

 

Sounds normal if performance doesn't suffer. Mine pops like crazy, sometimes with a staccato/machine gun sound when the throttle is blipped when cold. Just occasional shifting backfire when warmed up.
Do you have a lot of soot in your tailpipe?

 

Thanks Muzik but I don't have AIM anymore. Guess I need to download it again.

Toadman, my performance does suffer. It used to run badass but once it started doing this it runs like crap. Nothing over 6k, it just quits pulling.

 

I assume the first thing you checked was the map sensor? Seeings how you recently did plugs...

 

Yes I did.

 

Also make sure you got all the plug wires back on tight and fully connected.

 

Compression test time. It sounds like you may have blown your seal. What is your idle vacuum reading??

 

beware...that is not normal....

i watched a tech from xs at the track blow his motor when it was running like that.

i dont know what the prob is though...sorry

j

 

Did it start AFTER you put the new plugs in?? Maybe you got a bad batch or something???

 

I changed the plugs to see if it would help, no such luck. Boots are on good. Vacuum reads between 0.5 - 0.7 at idle, usually right at 0.6.

Guess I'll get a compression test done. Pray for me guys.