A B737-800 EXPERIENCED A WIND GUST AT 100 KTS ON TKOF CAUSING THE ACFT TO VEER RAPIDLY LEFT FOR A ABOUT 1 SECOND.

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DURING TKOF FROM ZZZ AT ABOUT 100 KIAS THE ACFT VEERED TO THE L FOR ABOUT 1 SECOND AND THEN CORRECTED ITSELF WITHOUT ANY PLT INPUT. ALL ENG INDICATIONS; FLT CTL INDICATIONS AND ALL OTHER SYS INDICATIONS WERE NORMAL. DURING CLBOUT I BEGAN TO QUESTION THE FO WHO WAS FLYING THE AIRPLANE. I ASKED HIM IF HE HAD KICKED THE RUDDER. HE SAID THAT HE HAD NOT. AS WE CLBED OUT I CALLED DISPATCH AND ASKED FOR A PHONE PATCH TO ZZZ1 MAINT. I DISCUSSED THE SITUATION WITH MAINT AT LENGTH TO FIND OUT IF THEY HAD ANY IDEAS AS TO WHAT IT MIGHT BE. NOTHING DEFINITIVE WAS DECIDED. I THEN TALKED TO DISPATCH ABOUT WHERE WE SHOULD LAND THE AIRPLANE. WE DECIDED THAT ZZZ1 WAS NOT MUCH FURTHER THAN ZZZ2 AND THAT THE WX AND MAINT AT ZZZ1 WERE VASTLY SUPERIOR. WE DIVERTED INTO ZZZ1 AND DECLARED AN EMER ASKING FOR THE ARFF EQUIP TO BE STANDING BY. AN UNEVENTFUL LNDG WAS MADE. IN RETROSPECT IF I HAD TO GUESS WHAT HAPPENED I WOULD SPECULATE THAT A PLASTIC BAG THAT WAS ON THE RWY JUST PRIOR TO THE SWERVE WAS INGESTED BY THE L ENG. THE ENG LOST PWR FOR JUST ENOUGH TIME TO CAUSE THE ACFT TO SWERVE WITHOUT THE ENG INDICATIONS CHANGING. MAINT IS DOWNLOADING THE FLT DATA RECORDER. I WILL BE VERY INTERESTED IN THEIR CONCLUSIONS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT THE FLT DATA RECORDER INDICATED A 10-15 KT CROSSWIND GUST CAUSED A MOMENTARY 10-15 KT AIR SPEED DECREASE. THERE WAS SOME WEATHER IN THE VICINITY BUT NOT CLOSE ENOUGH THAT THE CREW WOULD SUSPECT A WEATHER COMPONENT TO THIS EVENT. THE ACFT MOVEMENT WAS RAPID AND SEVERE ENOUGH THAT THEY SUSPECTED EITHER AN ENG MALFUNCTION OR A MOMENTARY RUDDER HARD OVER.