89 TBird Fuel pump?

I'm posting this for a friend who just bought a used '89 TBird 3.8 engine, 60K miles about 2 months ago, ran great until today. Now it's starting to hesitate while driving. Seemed to do it so far just
driving on 35 mph roads after engine was off a couple of hours. Seems OK on freeway after warmed up, but stopping at the end of the offramp, it stalled. Idling in the driveway it stalled, but started again. Fuel pump? The weather here has been in the teens last few days, but symtoms just started today. He just had an Bosch O2 sensor replaced 2 days ago, what's the possibility of that gone bad or installed wrong? We were thinking fuel line freeze up, but it was colder last week with no problems (Cleveland, Ohio). Any advice, thanks much.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
dke3591 wrote:

This sounds more like a vacuum leak than anything else, by your description.Possibly an IAC failing. The frigid temps we've been having tend to bring out the worst in older cars. I'm about 30 miles west of Cleveland and work in town, email me at xtadkins at gmail dot com. Maybe I can help in person.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

you just replaced the O2 sensor? Did you pull the battery cable and blank the computer? theses car "learn" if you change an engine parameter, the sensor now supplying good data, for example, the rest of the learned settings my be off. It may take several off start run cycles for the computer to adapt to the new settings. If the car restarts every time I would not think its the fuel pump. Check for vacuum leaks as suggested, Also check the IAC and TPS voltages with a meter. One of these may be causing the stall as the throttle is released
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.