I have a 2003 2.2 manual transmission and it seems to be sputtering a lot when I'm accelerating when switching from gear to gear. The sputtering stops as soon as the RPMs reach about 2500-3000. Then starts to sputter as soon as I switch gears while the RPMs are lower and so on. There is no "check engine" light and no codes. Plugs and boots are less than a year old. Kinda stumped on what to check with no CE light or codes..anyone have or had the same problem?

full tune up spark plugs / wires / fuel filter / air filter / 02 sensor.