Pontiac Repair: 1993 Pontiac Bonneville Cold Weather Check Engine Light, pontiac bonneville, auto parts stores

Question
1993 Pontiac Bonneville SE 3.8:  Warm weather the car is fine but when the weather gets cold (under about 40 degrees) the check engine light comes on and the car will not shift to overdrive on the highway.  Also if I floor it it doesn't shift down and runs like it is running out of gas or cuts out.  Idles fine.  When the check engine light periodically turns off it starts running and shifting fine again.  I have changed the fuel pump, air charge sensor, coils, plug wires, plugs, air filter, fuel filter and probably some other small things and cannot find the problem.

Answer
Hi Craig:

you first need to find out why the engine light is comming on/ what the code is. The 2 issues here may be related. most of the big box auto parts stores will scan codes for free. See what the code is and then you can go from there untill you know what is going on your just wasting your time  and $ throwing parts at this in hopes to find the right part to fix it. write me back when you find out what code(S) are set. Good luck :)