2003 EXP LIMI V6 studder problem PLEASE HELP!

[titanEXP]

Hello everyone,
I have a problem with my 2003 EXP 4.0L V6. At Idle, Acceleration from stop and while driving at low rpm it will sometimes stutter. This doesn't happen all the time but seems to happen more after starting the car and putting it into drive or reverse.
I have done the following within the past 6 months Brake fluid, trans fluid and coolant flush, plugs, wires, all wheel hubs,pads and rotor, fuel filter and pcv valve serpentine belt,belt tensioner, and I just recently did the crank position sensor because service engine soon light came on and I went to autozone to have it scanned and the code PO316 came up witch said miss fire at 1000rpm's check or replace crank pos sensor. Well I changed it and service engine soon light has not come on since.
Can someone please help me with this prob that I'm having? It will be greatly appreciated.

 

[ragajungle]

hopefully when you changed the plugs you used either Autolite or Motorcraft... Those are about the only plugs that will work with our engines

When you say "stutter" do you mean stumble?

 

[titanEXP]

I would say stumble and sluggish. I drove it yesterday and when I got home and put it in the garage it smelled like rotten eggs. I revved the motor a few times and it sounded like maybe the catalyst converter was clogged. Right around 1200-1300rpm it felt and sounded rough. What do you think? I cant remember what type of plugs and wires I used but I think they were both motorcraft. I usually like sticking to the fdactory stuff. I use motor craft motor oil and oil filter all the time too.

 

[xlt03]

I'd check the IAC valve and perhaps clean it. I too was getting the slight shuddering and usually when vehicle was cold. Cleaned the IAC and problems seems to have stopped. As to rotten eggs I'd say catalytic converter.