Watching this one closely. My neighbor'* '91 LeSabre is doing the same thing. I was gonna start by checking the output of the IAT sensor with the ECT sender. If the computer thinks the car is warm when cold, then not enough fuel to go.

If either of you need an IAT, I've got a couple extras

hhmmm ok does tech info have a chart that shows the resistance reading at different temps for the IAT ???

A simple thing could be condensaton freezing in the lines or filter, Has he tried using some dry gas?

if it was a faulty IAT it would set the SES with a DTC 23 of 25

Yeah but, it may be the IAT or the ECT sensor. And maybe one or the other can be bad enough (but not completely closed or open) to cause starting problems without setting a code?

I was just gonna say that.

Good suggestion.