hesitation/misfire at 6k
 

I suddenly had a loss of power the other day - my engine was hot and the car seemed to loose all power. I pulled over and thought i noticed smoke coming from under the car. I let it cool and then began driving again - how it "stumbles" or misfires at 6 k rpm. I changed my coils and no change. I don't believe it's in limp mode b/c this is a stutter at 6k and sometimes it goes past that point without issue - any suggestions?

1.) Not limp mode or you wouldn't get past 2-3k
2.) What color was smoke and from where? I know under the car, but could you be more specific on area? was it White? Dark?
3.) How is your coolant level....still okay?
3.) Changed coils, but didn't mention plugs(how old are they)? Stock ignition? How old are wires?
4.) Is your CAT glowing red after driving? Can't help but wonder if you have a glogged CAT starting to show up?
5.) Any other CELs? You got an AP right?

No gonna say what my first hunch would be without knowing a little bit more.

I do have an AP - however my USB cable is acting weird - it powers up the AP and gives me menu options/recognizes vehicle - but when i try to read codes or uninstall it states cable misconfigured or not connected - so I am ordering a new cable/dongle b/c i am afraid i bent it and now it wont connect. I didn't check plugs - ignition is stock - cat not glowing - smoke was for a second and appeared white but was so quick it was hard to recall - no cels but may be masked by mm maps? Coolant seems ok...plugs are about 1yr meaning about 10 k miles...

thanks for the effort

update - dealer said possible new engine - but had to run tests - then they stated coils were reading improperly and needed replaced - advised them they are 1 week old and they did a decarb tsb and said since no check engine light they can't isolate the issue even though they have the same hesitation and misfire findings.

they asked me to drive it more and bring it in when i get check engine light - hesitation seems worse and now cruising at 4 k shows hesitation and is bad enough my head bobs a little...

any advice?

My car, an 06, started that one day so bad that it would shut down and not restart until it cooled off. I took it to the dealer and they replaced the plugs and wires but not the coils and it still did the same thing. Took it back and they decarbed it and it worked better but the problem did not go away. They decarbed it a second time and it cleared up. Now, about 8K later (29k on the engine) it started again in this oppressive heat. I have not driven it since but I have to drive a lot in town so do not open it up as recommended as often as I should. When it is cooler I will take it out and run it to clean it out and see if the problem comes back. I probably need to replace my coils in the meantime.

It seems to occur when it is hot out. The engine, when it does not hesitate at high RPM's runs very strong.