sudden loss of power?
 

I just came back from a trip to Las vegas and on the way driving there from LA I noticed that the car would suddenly loose power for about half a second and then regain power again..... when that happens it seems like someone taps on your brakes just a bit and it gets really annoying after a while. I thought it was my driving but then I tried the cruse control and it still happened.
I dunno if it had to do with factors such as weather or AC, it was a pretty hot day, driving around 12noon to vegas, AC was on, temp ouside must have been 100+ and then it started happening as I was about half way there. So I tried switching off the AC and driving and it was still happeneing but not as noticeable....
It was even more noticiable when I got into vegas. it would happen at approx 2200 rpm for 1st, 2nd and 3rd gear and 2800-3200rpm for 3rd and 4th gear.
Then on the way back from Vegas I was driving at 12 midnight and had the AC on all the way an it didnt' happen once on the entire journey back.

Has anyone has this happen before?

Is my engine gonna fail soon? I was pretty worried the whole time I was driving there. Should I bring this up when I go back to the dealer?

Also is it necessary to turn off the AC while driving through the desert?
And is it necessary to make a stop to give the engine a rest in the middle of a 4-5 hour trip?

Hot day-bad performance
Driving home at midnight(cooler)-everything is fine
Do you see the trend?
At very hot day you have AC on, which is extra load on engine. ECU will probably have to retard timing to avoid detonation.
I notice loss of performance on very hot days too-like "stumble and go".
Personally I am not worried about that.
Alex

I had an older car with the same issue - very noticeable "dip" in power for a second at varying intervals, but only when the car was hot, and more so in hot weather.

Has your check engine light come on? How serious is the "dip"? Another example was my Miata - with the A/C on, anytime the compressor would start up, there was a very noticeable "buck" from the car. Small engine, plus very light car = lots of engine "feedback" when something kicks in like this.

In my older car, it was a bad sensor - and it did trip the check engine light every time it happened.

It is normal to have a drop in engine performance when the AC compressor kicks in, and many cars (not sure about our Pros) actually have the compressor kick on WITH OR WITHOUT using the AC - not sure of the reason, but I know this does occur on some cars, and I have noticed it on cars I owned, with similar symptoms - a buck with the AC on, but a much-less-noticeable-but-still-there buck with the AC off.

Take it to the dealer - what have you got to lose?

im ok with the weather explanation....but why did it happen on all gears,at almost the same rpm?
I guess the ecu is an issue here...

hey hihoslva- if you have the defogger on it will cycle the a/c on and off. maybe that is why the a/c comp. was on when the a/c was off?
it sounds to me like it is more of either a spark plug wire or fuel injector or ecu issue due to the power loss at a certain rpm, but alot of the time that will trigger a check engine light. a buddy of mine had a similar problem on his mustang, a new $1200 ecu (warranty item) fixed it. he had to take it to the dealer 3 times before they could duplicate the problem.