Saab maintenance #4: Broken Vacuum Check Valve

Close up of the vacuum check valve

This morning, as I was driving, I experienced some shuddering when the car slowed down. At idling, the shuddering was more obvious. It was as though the car was trying to find the right gear, or misfired. The initial thought was it might be a coil pack problem, for which I had a spare part as a back up. But as I googled to confirm the root cause of the problem, it looked more likely to be a vacuum line leak as coil pack problem usually causes misfiring at higher rpm (and my engine shuddered at low rpm or idle)

Popping up the bonnet, I inspected the lines and true enough, I found the vacuum check valve broken. Hopefully there is no other leaks, and we will find out more as I bring the car to the workshop tomorrow.

Location of the vacuum check valve

Saab maintenance #2 – check engine light and fuel cap

This afternoon, as I drove out of petrol kiosk after the gas fill up, the “Check Engine Light” (CEL) on my main instrumental cluster came on. Immediately made an appointment with the dealer to bring the car for a check tomorrow.

So in the meantime, I googled for the possible  and common cause of the problem, and interestingly top in the search list pointed me to the fuel cap not tightened properly. I wasn’t convinced by the explanation, but then I was telling myself, no harm trying since it is not difficult remediation to apply.

I went to the car, open the fuel cap door, and found that I could tighten the fuel cap further by one turn!  I then reset the ECU by taking out fuse #2 and #4 and restarted the car. The CEL no longer appeared, although I was experiencing some rough engine idling. I thought it was just a case of ECU adapting after a reset, and true enough, the engine idle speed stabilised shortly after awhile. I drove the car out for a test spin, the CEL did not light up even as I “boost” the car.

So the problem was finally solved! Reflecting back, I realised the problem probably had occurred at the petrol kiosk. The petrol station attendant did not tighten the fuel cap after the fill up, resulting in the CEL. Nevertheless, it was a good inexpensive lesson learnt, and again it’s internet and google that came to my rescue!