Engine Bog down and backfiring
 

I have had a progressive problem. When my engine heats up to about 96deg it sometimes starts bog down to the point that I have no power and nearly stalls. I have to pump the gas to keep it running but cannot get the RPMs above 4500. While I pump the gas it backfires and does not have enough power to move the car. After a few minutes of looking like an idiot on the side of the street I clear the problem by constantly pumping the gas.
Also I found that when I press the gas the RPMs fluctuate about 700 RPMS. Meaning like it is losing power for a split second and then returns.

Since I have had this problem I have installed:
Upgraded fuel pump
Custom K&N combo intake air box
APexi Power FC
new plugs
new gas filter-pain in the *X*#@ to change
New MAP sensor
New Apexi down pipe
Racing beat exhaust

I have to re-install the old computer to check the codes and it comes up with the MAP sensor, or sometimes nothing.
I have taken this in to my local shop (RX-7 Specialty) and they can't figure this out. I will try the additional grounding but this sounds more severe than hesitation.

Please help!!!!!!

No need for a poll....


Have you checked/tested your water thermosensor?

I replaced the water thermosensor already. It was one of the codes that come up.
I grounded the battery last night to the engine using some of the recent info in the forum and will test today.