99 Black Bird T/A

iTrader: (4)

My T/A finally threw the SES light. The car sat for a few days and the SES light went off when I started the car. I drove it for two days and the SES light came back on.

Scanned the car last night. The codes were the ones for the front O2 sensors which I will replace tonight. Given that they are the orignal ones, I'm not surprised.

However, the other code was air in fuel tank. I've replaced the gas cap with a new locking one and still get that code. The seal on the new cap looks good. The seal on the old cap was bad.

What else can cause air the fuel tank?

Thank you.

69LT1Bird

iTrader: (1)

What code did you pull, its too much hassle to go looking for the code, if you know it, post it.
There is a sensor on top of the sending unit that measures pressure in the tank. Check that, you have to take the tank down to physically check it or get a schematic and a meter and check the outputs to the PCM to see if they are still within specs.

Tuner@Straightline

It could also be anything that has to do with the EVAP system, I'd guess it's the selinoid.

99 Black Bird T/A

iTrader: (4)

The evap code was p0135.

Thanks for the tips.

2001NBMZ28

That's not an EVAP code, EVAP would be P0440, P0442......

99 Black Bird T/A

iTrader: (4)

hmmm...after I change the O2's etc I'll get it rescaned...thanks for the heads up I was going by what the guy at the parts store told me.

2001NBMZ28

If he was wrong on the EVAP code I wouldn't trust his diagnosis on the others either. If you're throwing codes for both precat sensors simultaneously it could be an indication of something else going on, for example running lean on both banks, and the 02s are fine.

99 Black Bird T/A

iTrader: (4)

Replaced the O2's today and cleared the codes. After 50 miles no SES.