I am posting for my son who just moved and has no internet yet. He has 2002 A4 1.8. It died while driving to work. We did some research on here and replaced the Cam Position sensor. No luck. Car has fuel ( checked at fuel rail and hear pump) and spark. He and a buddy pulled the motor and replaced it with another used one. This just before the vag-com reader came. Long story short. This motor almost does the same thing. It will crank and get one backfire/pop through intake then just cranks. Only sensors same are cam position (tried both) and crank position sensor. We get 16725 code Cam position sensor - implausible signal. Wiring looks good, have not checked it with a meter yet. We also thought about cam timing chain, but same results on two motors? Thanks