Just stared to day randomly.

It will sputter at low RPMS. I have only noticed it when i'm at a stop and taking off. It has a rough feel when idling, the idle speed is fine but the exhaust is like thud..thud..thud, and i can physically feel this not just hear it. I did notice when i pass cars the small exhaust leak under the front seats sputter but does not sputter from the tail pipe.

I have new plugs and wires, and a new fuel filter. I also do not have a check engine light on, my commutes are typically 10min or less. I drive in a city lost of stoping and going.

Could it be the exhaust underneath the front seats? this is were i hear it the most, possibly an O2 sensor?

 

also my MPG has gone down from roughly 400 a tank to 350 or less, so im thinking its the 02 sensor.

 

Rough feel & thud sound to me like the exhaust leak along with possibly the exhaust pipe physically hitting against the underside of the car. Check that out. Grab the exhaust pipe & push it around to see if you can make it hit something.

The loss of MPG might be a separate problem.

 

turns out to be clogged egr valve.