What next to do after fuel pump replaced, oxygen sensor, check engine light still on on 2000 Chevrolet Prizm

Check engine light came on in April, had oxygen sensor replaced after receiving scan from Troubleshooting : PO171, then had fuel pump replaced after diagnostic from Chevy Dealer said need new fuel pump because of low pressure. The Probable cause from the first scan said 1) If bank one and two codes set together suspect 2) fuel pressure or MAF sensor 3) Oxygen sensor defective 4) Ignition misfire-repair 5) Fuel injector problem The CEL went out for a brief time after receiving car back from auto repair person, but as soon as I was down the hwy a half mile it came back on. Please help me with next step. Thanks!

by in Atlanta, GA on June 02, 2010
2 answers
ANSWER by on June 02, 2010
wow, somebody missed the basics. 171 comes from a vaccuum leak in most cases. the others are possible but only after you check the basics first. you need someone who knows what htey are doing and wont waste your money. Roy
ANSWER by on August 14, 2011
spark plugs