99 Es300 Misfire On Cylinder 1 And P0171 Error Code

[phattdaddie]

I have a misfire on cylinder 1 (check engine light flashing and vcs off), the car has a bad miss and hesitate to pick up speed. I replaced the coil on cylinder 1 and it ran fine, but after a few days it begin to miss again. I have yet to figure out the P0171 error. i have replaced all the spark plug, could i have gotten a bad Coil?

[tomf]

I had the P0171. I had a bad mass airflow sensor. Try cleaning your mass air flow sensor. I had to replace mine.