my car does that too.... I gotta get my brothers tester to read the codes (mine has check engine too) I usually give it some gas and it warms up ok... but I have noticed a decrease in performance.. which leads me to believe something emissions related. Also, i get the freaky thing where to car will accel faster if I put the pedal down 1/4-1/2 the way down instead of to the floor.... Almost like the car bogs down if you floor it before 30 MPH... maybe a throttle positioning sensor... grrrr too many sensors...
Jonathan
Jonathan