Question

2002 Volkswagen Passat 1.8T have p0171 with p0300 thru p0304 what is the possible problem?

Answer 1

This indicates a possible vacuum leak or bad mass air flow sensor. The 171 code means the system is to lean.This can cause the multiple misfire codes. You should also check the fuel pressure as well.

Answer 2

P0171 VOLKSWAGEN Code - System Too Lean Bank 1
Read more: https://www.autocodes.com/p0171_volkswagen.html

P0300 VOLKSWAGEN Code - Random Cylinder Misfire Detected
Read more: https://www.autocodes.com/p0300_volkswagen.html

P0304 VOLKSWAGEN Code - Cylinder 4 Misfire Detected
Read more: https://www.autocodes.com/p0304_volkswagen.html