The Mustang Source - Ford Mustang Forums - 2000 GT with incredible loss of power on warm or hot weather

Hello all! I'm new here looking for help. I am not a mechanic but I know a few things. It's been two years since I bought my 2000 GT with 60K miles, almost stock, just cat back Borla Touring's exhaust and Eibach's springs. I bought this car at the end of the summer of 2017 and is very clean inside, well maintain, etc but I felt a slow acceleration after a few days of driving it, as days pass by I checked the throttle pedal and it was very loose so I put a few zip tights and the car was running much better so I thought that that was the issue with the lack of power. I also noticed the car stalled on me a few times while parking in reverse only. Every week the car stalled at least once a week. My first winter I drove the car very little and the stalling didn't bother me that much until the summer came in and the first day of real high humidity and heat hit us is when I felt something bizarre! The car was running really bad, very sluggish, it felt like it was running with half of the engine, no loud sound from the exhaust and super heavy to the throttle. I thought the car was in limp mode but I never got a CEL. A month later the car stall while I was park but switching to another while I was waiting for the green light, in that moment I knew that this symptom was getting serious so I drove a few miles and did a quick stop at the only place that was open Sunday afternoon and the mechanic showed me a leak in the front seal of the tranny (auto). From there things got even worse because it was leaking right on top the cat's and it was a mess so decided to buy a remanufacture tranny + some sensor (speed and neutral) and a tranny mount. BUT no luck! everything was the same, the sluggishness to power loss was the same. Obviously the tranny wasn't the problem.
I took the car the Ford dealer for a proper inspection to see if the tranny was properly installed or whatever and Ford Reflash the ECU so the tranny relearn the shifting points, etc. I left the shop with the car even worse. No power, no sound from the exhaust..
From there I took the car to several shops who didn't have an opinion because there are no CEL or codes. After a full tune up the car was the same.
The winter came in and the car started to run again as is supposed to be but it doesn't feel natural.
This year I replaced the fuel pump and fuel filter, new MAF, new coil packs, new TPS, we check the radiator and replaced the thermostat and the coolant sensor as well. That night the car run smoothly and it was burning tires! I thought that was the problem but it only lasted one night, the next day the car was running weird again.
After replacing the Fuel pump the car was running again! like new bu tit only lasted a few days (this was a month ago) because the warm weather made the car run slow again.
Two weeks ago I decided to follow some advised from a few people, delete the cat's so I did! BBK X pipe, new O2's (NTK from American Muscle) with MIL's. While the weather still playing between 50's and 60's here in NY the car it's been running OK but as soon as the weather goes up to 60's the car is running like crap again. I spoke to a guy who said that he works for the Ford in ND and he asked me for videos and data from my scanner so last weeks he said to me that he consult with his co workers and they watch the video and they think that the EGR is the problem. OK I said let's buy a EGR so I got one last Saturday and it's been a week driving the car but again...the weather it's been ****ty here (between 50's and 60's) so is hard to say if this will resolve the mystery BUT last Thursday the temperature went up to 67 around 4pm. I checked the weather that morning so I escape from work for few minutes to test drive the car around 1pm and it was 62 when I test drove the car in high temperature and the car started sounding normal and it drove normal. that same afternoon I went home after 5pm but the temperature went down fast! from 67 to 57 and I did felt the powerless but not so severe as the last time.
My question is: Does anybody have some experience on this rare symptom? What can affect the engine so fast or be so sensitive to the temperature changes? This is not something that takes minutes to happen, it happens right away at first cold start in the morning, afternoon, etc. It seems like something is over heating.
The ABS light it's been on for almost a year.

Thanks for your help, is greatly appreciate it. I know is a long story but I think I describe everything since I bought it.

Thanks!