Hey guys, I've got a 1987 trans am gta, with a 305 and a 5 speed. I recently took the leap and did a header swap. Which resulted in deleting the egr system, me accidently breaking the ac line which lead to a delete, and due to header fitment I had to remove the heater core lines. (I live in FL so no worries about the heater.)

SO I put the car back together and had a vacuum leak issue which is now fixed. I HAVE NO VACUUM LEAKS I have sprayed all the gaskets I replaced with brake parts cleaner and I have no idle fluctuations. I also had the MAF sensor on backbackwards which was making the car run terrible, but have fixed that and it's better now.

My issue is this; the car starts first crank, idles around 600-700 rpm, (it's a digital dash so it's a rough estimate) when I Rev it out of gear it sounds good and healthy. When I drive the car and put a load on it however, it doesn't run 100%. It feels rough and has a loss of power, compared to before I did the header swap. The biggest problem is when I come to a stop from putting it under load, it sputters and eventually dies out unless I Rev it to keep it alive. I should note that the car ran absolutely perfect with no misses before this swap.

Here's a list of everything I've done with this swap.

Heater core, ac, and egr delete.
new spark plug wires(also cap and rotor are only 3 months old.)
cold air intake
headers(wrapped)
new o2 sensor, but it's on the driver side now compared to stock being on the passenger side. I cut and ran the wire longer.