Hi All,

My first post here. I have been having an issue with my '06 Scion XB (150k miles) that started about two weeks ago.

This is occurring after the engine is warmed up. If I am slowing down, for instance, on an on ramp of a freeway, and begin to accelerate as I merge onto the new freeway at around 50Mph as I accelerate more the engine hesitates, and stutters for a second, and then begins to accelerate up to 70Mph. This is also happening at stop lights once in awhile. I can only compare this stutter like a "cough" effect, sort of like it's not getting enough gas or something.

The transmission is shifting smoothly from all the way through the last gear, and it's not reving high when shifting, nor is it shifting hard. It's only during sudden acceleration that this occurs.

Any ideas what could be the cause?

 

Definitely could be a problem with your fuel injectors. Either clogged up or carboned over.
I'm kinda surprised your check engine light isn't on though.

 

Can of Sea-Foam
Replace your plugs.
Inspect Air Cleaner.

 

I ended up replacing air filter, all four spark plugs (premium quality), cleaned and dried the spark plugs wells, and Lucas fuel injector cleaner.

Runs great now. I'm very relieved that it was a relatively cheap fix (about $50).