I have a 2003 Volkswagen Jetta, which recently (at 110,000 miles) has developed an intermittent no-start condition. The engine will turn over -- seems the starter is working, but can't start the engine (similar to the situation when the ignition wires are bad). The ignition wires,plugs and ignition pack were all replaced several months ago.
I've made 3 attempts to fix it, but no lasting solution has been found. Per my mechanic a diagnostic scoping did reveal a code for an intermittent short and a faulty oxygen sensor. The oxygen sensor was replaced, but the no-start reappeared in a couple weeks. The fuel pump was changed. Again the problem reappeared in a couple weeks. Then a substandard positive battery connection was corrected, but the problem reappeared in a couple weeks. My mechanic said it could be some relays. What would you suggest trying next, as this is getting very expensive for me?
I was wondering if the fault could be in the computer, by natural wear or design.