I need your help

friends good evening I have a different problem I couldn't find the reason

I have a peugeot 307 xsi 2.0 138 hp

my vehicle only has a singing problem while climbing the mountain, it does not do it on the straight road, it does it while climbing, for example, I do not climb the mountain slowly, 1st gear 2nd gear 3rd gear there is no problem, 4th gear is 2200 revolutions, 1-second misfire then I continue to the 5th gear again I keep singing for around 1 second in 2000

We couldn't find the cause of the problem, is there anyone to help?

I get supressed from the bobbin. The misfire is like the engine has stopped for 1 second.

I did not look at the coil, I suspect the first spark plugs and changed them immediately when I tried today, did the same again, but I do not know the coil yes 1 second car is gone then it goes and continues

What I think is strange is that he only does it while climbing the mountain.

I'm following
It seems to me that it's happening in less than 1 second but I'm not sure
Edit vPro 2015-04-05 23:27:21

What is the fuel of the vehicle

Could be a coil or you are pressing less on the flat gas and the ignition raises when the vehicle accelerates without difficulty, but you can press the cone on the slope too much, and the vehicle cannot raise the ignition for the vehicle. But the guess is the diagnosis. It is a research that goes from cheap to expensive. If you have a spark plug cable