Sensor or Computer problem

I am new to this website. I need help regarding my car. I have cutlas ciera 2.5L year-1986.
I put reman. motor at 170K. last year I changed the MAP sensor because it was showing the code. This year I put a new TBS Sensor in March as it was showing the code. it was running very smooth. now since one month it is showing again codes for to replace both MAP Sensor and TBS Sensor also the book says wires to ECM. Because of this starting problem is there. it will not start unless I put starter fluid in the FI. I erased the code twice but it is coming again the same codes.
These both sensors were purchased in AUTO ZONE.
Please tell me whether to change these two again or is there any other problem?
Thanks to you all for your help.

More than likely the fuel pump is weak.
Is it the original pump? If it is, it would be a good idea to replace it anyway. It's long overdue.:banghead:
What were the codes?

I had to replace the fuel pump on my '87 2.5L (only 140K miles) because the pressure was marginal.

More than likely the fuel pump is weak.
Is it the original pump? If it is, it would be a good idea to replace it anyway. It's long overdue.:banghead:
What were the codes?

I had to replace the fuel pump on my '87 2.5L (only 140K miles) because the pressure was marginal.


Thanks for the info.
Yes I have changer the fuel pump around 200K.-from Auto Zone.
the Codes are 21 and 33 if you have a repair manuel please read the comments and advise.