Hello, I have a 2004 Audi A4 1.8 Quattro. Lately it has been dying while stopped, after restarting the vehicle it gives me a EPC signal. Yesterday, it completely died on me, and wouldn't start for roughly an hour, then on my way home it died at a stoplight again and wouldn't start. I bought a crankshaft position sensor, and a camshaft position sensor. This far I've only replaced the crankshaft, the car hasn't died since but now the car is misfiring, and shaking somewhat when accelerating. What should I do? Is the crankshaft I bought defective?

 

Don't start throwing parts at it until you pull the error OBD codes from the ECU. It will tell you what sensor is causing the problems. If you get a MAF sensor error, here is a way to test it. Disconnect it. Fire it up and see how the engine runs. Drive it. If it runs better, then it is the MAF sending erroneous data on air flow to the ECU. The ECU can run the engine just fine on with the O2 and other sensors. However, if the MAF is "lying" to the ECU, it can cause weird running issues.