i have a 2.8 liter camaro with a manual trans. everytime i shift from one gear to the next, my car backfires. it does this until the t-stat opens. any ideas what could be causing it or how to fix it? there is an exhaust leak just past the convertor, could this be a reason? any help is greatly appreciated.

 

my s 10 blazer with a 2.8 v6 did that too, i took it to a muffler shop figuing it was the exhaust cause it didnt do it till i had my glasspack put on and he gave me some lame excuse and sent me on my way..end result, still backfires...so sold it and bought another maro

 

Living where ya at, I'd say fix the exhaust leak or see how to securely fix the leak. New pipes or what.
NEXT find any cracks on the manifolds, if any.
Look for white powdery markings on the manifolds.
Ya getting a "pop" or "big bang"?
Probably a "pop" sound. Check the pipes that could be the true cause.

 

yea, its a big pop. would it work to just cut the convertor off it? thats what i had planned on doing anyways.

 

The factory exhaust system is quite good.
NOT PERFECT yet.....
How stretched is your timing chain?
How many miles on ride?
What ya done to it lately?
Give clues.....
Extra air entering exhaust can cause pop.
Where does it come out (the pop)?
Engine, pipes?

 

im not sure how stretched the timing chain is, but it doesnt seem to be off or anything. it runs fine, it just idles high when its cold and the back fire. it has 131k miles on her. as far as any mods or anything, i havent done anything to it yet. just tune up and stuff, but its done it since i bought it. and the pop sounds like its coming from the pipes. i dont know if that helps you out at all. thanks

 

that sounds exactly like what my blazer did, i had a few people tell me it was my cat converter doin it, never got a chance to cut it off though...

 

Here's what's going on.
The chain is stretched, so the timing is off.
When cold, extra fuel introduced.
This mixes with the air being sucked into the exhaust system by hole, it ignites the stuff.
Check chain stretch easy.
Put 17mm socket & ratchet on crank. Pop off distributor cap. Move crank by hand motion and observe how long it takes to move the rotor.
Judge for youself how stretched chain is.
Fixing exhaust will also help.
All your "now needed projects" will be determined by how much ya wanna keep this ride.
PS these fixes will increase fuel milage and restore lots of power that has been lost.
AND help the current drivetrain last many miles more.
Is it labor intensive, certainly.
Ya got an old ride, it's part of the package.
Expensive, it can be. Or ya can save by doing work yourself. It's ya call how ya handle to the do project list.
Timing chain project is about $70-$100 in parts. Lots of labor. SO is properly repairing the exhaust.
Cutting off the cc isn't a solution. Replacing the CC for a newer more efficent item, is the wise solution. Ya can get CC's thru mailorder for about $60. Install costs about $40 (hour labor).

 

hey KED85,
thanks for the advise, ill take a look at it and see how much slack is in the chain. ill also look into a cat for it. appreciate it.

 

As I was just thinking about my own experience.
My Blazer used to POP every so often, usually upon deceleration from a high speed.
Eventually, I discovered a small hole in the pipe weld, before the CC.
My Firebird came to me with cracked exhaust manifold. Boy did that cause problems.

You may be going thru POS (Previous Owner Sybdrom)
Been there.
It can be a long haul back to a decent reliable ride. Try it one project at a time.

About the chain, as it gain/looses RPMS, the chain makes a shape like an "S"-advancing, then retarding timing at the same time. Yes that does/can cause havoc!
Good thoughts to ya.