Thanks for all the replies.

As suggested I read the codes on pin 4 LH-SFI module and got back a 1 which means no fault. The O2 sensor was replaced about a year ago.

Can it go bad so soon like this?

As to my gas mileage I get about 270 miles to a tank. That is with stopping the pump when it click with no overfilling as I found it to be impossible with this car until the low fuel light comes on. I drive 75 % highway with rest in the city. I only use 93.

Is that good mileage?

While I was reading the codes I also probed other pins and on pin 7 EA/CC/ISC I get code 6 - Starter lock-out/backup lamp switch (S16/3). I don’t think this is relevant to the problem I have but I will look into it as well.

I checked the vacuum lines that go to the pump and all is ok. I also checked the other ones that I could see and inspect and they were ok. I had changed the elbows, the ones I could get to, about 7 month ago. The switchover valves I could not find.

Where are they located?

What do I look for?

Does the pump coming on mean it is ok?

Thanks