pontiac_boy

iTrader: (1)

So last fall my old motor sunk a lifter and i pulled it with the plans of doing a stroker. In the mean time a buddie of mine totaled his Z28 so he gave me a smoking deal on the motor. I pulled it out and put my cam and sring on it so its basically the same setup i had before. I got the new motor in my can fired it up and it ran fine. I took it to my parents (80 miles away) with no issues. On the return trip home about 60 miles into the drive the SES light came on so i pulled over to see if anything came loose and found nothing. I got in the car and kept going. After a couple miles i could tell the car seemed to be bogging the the light started flashing so i shut the car off and coasted to the shoulder got out checked out the car again and found nothing. I limped the car the rest of the way home and checked the codes. IT was showing P0300, P0171 an air speed sensor malfun and the front 2 oxygen sensor heaters malfunction. I changed the air speed sensor, both 02 sensors, checked three different times for a vacuum leak, had a friend check for a vacuum leak, cleaned the mass air meter, then changed the mass air meter and checked the ground for the o2's. The way the car sits now the P0300 is gone and im just showing P0171 and the o'2 heaters. Im stumped. We hooked a computer up to it and at idle adding 25% fuel trim but if i take the Rpms up to 1800 it starts to clear up and the fuel trim starts to go down to where it should be. I am out of ideas and could really use some help? Thanks in advance.

I should also note that i had the car tunned last year with the last motor and the only changes i made was gears and a higher stall.