Originally Posted by Supa LA
I have had a similar issue of late in my 05 sti. My car doesnt jerk, just seems to hesitate. This only happens while crusing at around 2200-2600 rpm in higher gears, like 4th-6th. Its mainly when im trying to hold speed without the cruise on. Can bad gas cause this? My oil is fine and i have had no issues with the tune before? HOWEVER, the last oil change was with T6. The previous owner ran Mobil1 5w30/40 depending on season (hot/cold) All of this started happening about one month ago (roughly). When i give it throttle it powers thru just fine. I have seen no issues on lower gears or speeds.
big maf intake
3" straight pipe
several other minimal ones.
Interesting. I have heard stories about the engine "getting used" to the type of engine oil and responding differently when a different type is used. However, these stories involved the use of high-mileage oil and then switching back to conventional. The stick I drove regularly was years ago and it was a much different ride than a STI. I did notice some hesitation when I was in a higher gear than I should have been. However, that car had far less HP and torque then a STI.