HELP - sudden explosion sound whild driving

[omaromar50]

Dears,

I am new member to your forum, I have recently bought 2002 Envoy SLT with 190 KM.

The car seems to be having many complicated problems, but what I am concentrating to solve right now is, sometimes when accelerating I hear a very loud explosion sound, with black exhaust. sometimes I feel that the car engine is vibrating hardly and the acceleration is badly affected after the explosion, even more some times the engine stops directly after the explosion, but when I start it again it runs, but with very bad acceleration.

Sorry for my bad English, Appreciate all your support

[lhassebrock]

I would suggest you stop driving it and get all the codes read to see what's wrong with it. If ther's not already major damage, there will be soon if you keep driving it around.

[BanditGTP]

It sounds like it might be a backfire. I had that on a work van several years ago. After a while (and many backfires) it blew up my muffler and needed to replace the exhaust. I'm not sure what the cause was since my boss had the van repaired.

[Machoman]

yes it does sound like a backfire.

[omaromar50]

Dears
Thanks for your replies

What can be the cause for the backfire??

[GM Lover]

Originally Posted by omaromar50

Dears
Thanks for your replies

What can be the cause for the backfire??

Backfire is caused by the accumulation of unburned gases that suddenly burst or explode. Check for a clogged catalytic converter. Good Luck

[omaromar50]

Originally Posted by GM Lover

Backfire is caused by the accumulation of unburned gases that suddenly burst or explode. Check for a clogged catalytic converter. Good Luck

what can be the cause for unburned gases?!?!

[lhassebrock]

A missfire can cause the symptoms you're describing. Bad plug or coil. Are any of your lights flashing on your dash when this happens?

[omaromar50]

Originally Posted by lhassebrock

A missfire can cause the symptoms you're describing. Bad plug or coil. Are any of your lights flashing on your dash when this happens?

Actually no any lights showing
Before or after, but some times the dashboard is showing low oil level while it is ok.

[omaromar50]

I have to give a big thank to every one gave an advise in this topic, specially lhassebrock.

Actually, I have find one coil not working and I am going to change it tonight.
Is it normal for these coils to go bad, or there must be a reason that I have to search for before just changing the coil. any more advices?
is there a big difference between the Original and the after market ones?
BTW the installed is Delphi.

GM Lover,BanditGTP and Machoman I will go next to check the catalytic converter. what are the symptoms that it is clogged? as I hope the back fire will end after changing the coil, I hope so.

Appreciate all your help