Help with Misfire, Backfire, etc.

[dsmwv]

I've searched around and I can't really find help with this issue. My 98 GS wouldn't even idle correctly a few days ago. It would start and die not even 2 seconds later. I ended up removing the exhaust because the only way it would stay started is when I would detach the exhaust from the headers. When I removed the exhaust, I found the o2 sensor was just covered in black. It needs a new head gasket and there's a coolant leak. So, could the o2 sensor make it run like crap? or could it be out of time? I know the obvious head gasket and coolant leak but could that make it misfire/backfire while driving? I've only drove it maybe 20 feet and it started misfiring/backfiring. I would like to fix it because I'm really attached to this car.

I really appreciate it, thanks.

 

[dsmaz]

I had something similar happen when I blew my headgasket. I ended up having to rebuild my motor. You should take your head off and see how bad your hg is and check your pistons for slop or holes from running too hot.

 

[FalleN4ng31]

I ended up removing the exhaust because the only way it would stay started is when I would detach the exhaust from the headers. When I removed the exhaust, I found the o2 sensor was just covered in black.

I won't go into the HG portion of this, you already know what needs to be done there. If you had to remove the entire exhaust to get the car to idle, I'd look for a plugged up cat as well. Your downstream O2 sensor is only checking to make sure the cat is doing it's job.

Aside from the P030X misfire codes, are you throwing any other CEL's?

 

[dsmwv]

I won't go into the HG portion of this, you already know what needs to be done there. If you had to remove the entire exhaust to get the car to idle, I'd look for a plugged up cat as well. Your downstream O2 sensor is only checking to make sure the cat is doing it's job.

Aside from the P030X misfire codes, are you throwing any other CEL's?

I didn't actually scan the codes because I couldn't even get it to Auto Zone or anything. I really don't want to buy a scanner either but that's probably the only way I'm going to know for sure. I'm gonna invest in a new exhaust, seeing as that one was all rusted anyway. I think someone attempted to knock the cat out but all they did was plug it up.