4kq fuel pump relay question & O2 sensor reading

[Lines Peter]

If the fuel pump doesn't "prime" when you turn the key on, it could be a bad
relay or the wrong relay.  Also, make sure to tell the parts guy if you have
a 5-cyl or 4-cyl engine when ordering.  Just saying "4000" isn't enough.
The relay has a built in rev limiter which is matched to the engine.
Install the 4-cyl relay in a 5-cyl car and you hit a brick wall around 4000
rpm.  That's no fun :-)

Peter Lines