I just bought a 1996 Chevy C1500, 5.0 with the 4spd auto. I drove it about 80 miles after I bought it and it ran beautiful. The next day it started shifting hard and stalling, then the check engine light came on. I took it to the auto store to have it scanned and it came up with code PO122, so I replaced the TPS. The next morning it was doing the same thing. I drove home in the afternoon it drove perfect. This morning after about 15 miles it started doing it again and the check engine light came on again. At lunch I went back to the auto store (ran perfect) and got the code PO122 again, any idea's?