Buick Century 99 SES Shift Sol
 

Hi there fellas, I have a problem with my 99 Buick Century. It was given to me by my father, the car had been sitting fo roughly 2-3months, getting started at least once a week.
When i got it, I noticed the SES light was on, when i drove it it lacked power accelerating. I changed all spark plugs, wires, oil (and filters, cabin, main air filter and of coarse oil filter.
I still had the SES light. Then a buddy of mine had a GM code reader, I got the code P0753, shift solenoid A (1-2) Electrical.

I then proceeded and got a Transmission flush. Still nothing changed
I then added abit of Lucas Transmission fix, and I noticed that after driving the car for 30-40 mins when I stop and accelerate the car is back to normal!! I have my 1st and 2nd gear. Then obviously the next day its back to the 3rd gear again until it warms up. (at least it feels like 3rd gear!)

Anyone have experience with this?? I want to know should I get the solenoid changed, and I am Ok to drive it this way as money is a little tight at the moment!
Its gonna cost me about 300-400 to fix, I looked into doing it myself but its not as easy as dropping the pan on the tranny, its a side cover i have to take off and remove and support the engine, It worries me!
thanks, my email is markdexter18@gmail.com

I absolutely love this car, smoothest riding car Ive ever experienced