Unexplained RPM/power loss and dropping revs (posted video of problem)

[johnoski]

***NEW INFO*** (12/26/13)

This car is no longer under warranty. Draining the Tranny fluid, changing the filter, and cleaning out the pan, did not help the issue at all.

While I was with extended family over the past couple weeks, an uncle of mine suggested that it could be the fuel pump starting to go bad. He noted from his experience, that when they start to go bad, they will work fine at first, then after a few minutes they get hot and start acting up and can lose pressure. So I did a little testing of the fuel pump. Here is what I did:

1. Pulled up the back seat and removed the cover exposing the pump connections. I connected leads to the Positive and Negative wires (Brown and Black), and drove the car while monitoring the voltages present. When the car is driving normal or accelerating, the voltage is at a steady 13.78 +/- 0.02 volts. When I am braking or at a stop light, the voltage drops a bit to 13.62 +/- 0.02 volts. This seems normal to me since the higher voltage is when the pump is under stress, and the lower is when the pump is not. If I am not correct in this logic... please correct me When it did act up the voltage was all over the place. Sometimes it dropped between 13.5-10.5 volts, and sometimes it only dropped about 0.0 to 0.3 volts.

2. Second, I did a voltage drop test on both the positive and negative sides of the fuel pump power circuit. On the positive side the voltage was 12.59 volts with the engine off, and 0.46 with the engine on. This was obtained by connecting the positive lead of my multi-meter to the positive terminal on the battery, and the negative lead to an extension connected to the positive wire on the pump (brown wire). On the negative side the voltage was 0.00 with the car off, and 0.40 with the engine on. The negative was obtained by connecting the negative lead to the negative terminal on the battery, and the positive lead to an extension connected to the negative wire on the pump (black wire). Again, I think this is normal, but correct me if I am wrong.

I am beginning to believe this is a fuel pump problem. Since the pump is like $350-$400, I would like some other opinions before I pay for a new one.

Also, the CEL finally came on. I never thought I would be happy to say that. The plan is go an have those checked tomorrow at a local shop.

Thanks!