Car sputters and loss of power.
Check engine light comes on.

I forgot the exact code number but it said "Downstream not matched".
I know it has to do something with O2 sensor.

So can a bad O2 sensor make the car loose power?
What if I disconnect the downstream sensor?

Or how can make sure that its O2 sensor problem?

Car makes backfire pops if I gun it.

Checked the spark plugs, wires, fuel, all seems to be working right.

Car just don't wanna accelerate but if I really push it and let it pass 3500 rpm all of a sudden it picksup and feels powerfull.

 

I went back and checked the engine codes.

Apparently the O2 downstream code is gone after the new Catalytic converter install.

But now one more code showed up.

P0301 which I found out means
"Misfire Detected, Cylinder No. 1"*

The P1684 simply means that the battery was disconnected within last 50 starts.

Now what do I do about the misfire in cylinder 1?
Get new plug wire or how do I diagnose it?

There is definately something going on because car feels like slower than a 1.6 litre* engine and sputters.

*Found the codes detail on the following web:
http://answers.yahoo.com/question/in...9195234AA7qibL

 

what plugs are in it?
How old?
Wires - how old?
Both are rather cheap to replace

 

could be the wires, i know i put on grantinilli ones and i kept getting a misfire. But when i switched to mopar performance ones haven't had any problems(knock on wood).

 

Took the plugs out and regaped them little tighter with the guage.
The hesitation is completely gone.