Hi all,
I have a 1987 Pontiac Sunbird that throws a code 44 (Lean exhaust) after driving about a mile when cold. You can tell when it is coming because the car gets sluggish. Once the check engine comes on restarting it will smooth things out for the remainder of the day. This could be because it never gets to totally cool off again. I believe this occurs when the computer goes closed loop. I have replaced the O2 sensor and fuel filter. The other interesting thing is that I have dropped off 3 to 5 mpg. Any thoughts would be appreciated.

Check for vacuum leaks. I use a small propane torch used for plumbing work to search for the leaks that I cannot visibly find. Turn the gas on enough so you can hear it and move the nozzle around the lines. If the engine idle increases, you found a leak. Check especially around the intake manifold and catb. Good luck!

Just thought of another thing to check; the EGR valve. Some models you can manually actuate to make it is not stuck open.

Thanks for the thoughts Scott, I know my EGR caused trouble once before and you are correct that it can be manually actuated. Hopefully I can check your suggestions out in the next day or two
Tom