My guess is either bad plugs or cops.....If it were the cat the light would likely stay on. I currently have a bad cat and am waiting for the dealership (it is under warranty) to get it in stock, might get it sometime before Christmas if I am lucky.

 

Thanks for all the comments, folks. I STILL haven't made it to have the codes pulled yet, as I work 12 night shifts, and haven't had time yet.

I tend to think this is more likely a timing, electrical, computer, or fuel delivery issue, since it was such a drastic and sudden problem, and it totally went away, after a restart. Like Carlsson3 said, it felt like it dropped to running on only two cylinders, until I restarted it! I have put several miles on it since, with no problems. I would expect a cat, or plug, or COP problem wouldn't totally clear up with a restart. I guess, unless a cat got hot or plugged enough, that a sensor threw a crazy reading to the computer, and it compensated by going into a limp mode or something wierd like that. I used to do a lot of engine work years ago, but I really don't know a lot about the advanced systems of the newer engines.

I hope to get the codes pulled (if any) this week, and talk to my dealer, to see if they have any ideas or TSB's on this issue. I will keep you all posted, but please don't hesitate to comment with more ideas. TIA, JB45

 

well cats are covered under 8 year/80k and as for fred i had a bad cat that would only act up everyone in a while. which one are you waiting on? passenger side? i waited a week for a passenger side cat. the dealer around near me deals with TASCA so they have everything in stock. and my cop would act up only when under heavy load or hammering on it .... would shake like a bastard until it would downshift out of OD then smooth out. dealer tried playing game with me and i set them str8... i have been doing it for 6+ years as a mechanic.. tried saying that the TC was balooning up and the tranny might be having problem. told him go screw and figure it out lol only went to them because i thought it was a cat related issue because it was doing the same thing when the cat went bad... will be not dealling with them in the future... mother had a coil problem with her Fusion yesterday went in and they tried to give her the ring-a-round too... wanted to charge $1200 for 1 coil, trans flush, and diag!!! called them up asked them what coil was bad, brought it back to my shop and did the coil and trans flush for $174.71.. jerk offs!!!