Car Stuttering in Morning?!

[Matt's03GT]

I have an 03 GT manual. The only mods are an offroad X-pipe, o2 mils, short throw shifter, KN Filter, silencer removed.

If I have not driven the car for about 12-14 hours, when I start it and start to drive it stutters for about half a block then just stops. Funny thing is that it reverses fine out of the driveway and as soon as I start to put it under load it stutters for about the first 300 feet.

The car runs absolutley great otherwise. The only problems I have had have been with the CEL. I have an autoscanner and have read the codes every time it comes on. It is always the o2 sensor malfunction code. I erase it as I know the sims are not perfect (anyone know a fix for this)... Then about 3 months later it happens again and I do the little dance...

Any ideas, I am considering putting the silencer back on the air filter as I have read that there could be some downsides to having it removed.... Maybe I should just get new sims...

 

[Matt's03GT]

Mileage

Oh yah, it has about 12,000 miles and started doing this about 3 months ago...

Thanks for any help.

 

[Carl]

Mine's been doing that for a long time. If you let it warm up for a minute it doesn't do it. I have narrowed it down to an O2 sensor that isn't heating up fast enough. It's not off enough to throw a code, but if it doesn't heat up fast enough and start switching, then you get stuttering and hesitation until it gets up to it's operating temp.

 

[StngStr]

same here. I find that if I rev it up a bit before backing out of the garage it doesn't stutter when I drive down the street. Also, if you let it run for 30 seconds or so, it shouldn't do it.