1991 Nissan truck Exhaust overheating

I have a 1991 Nissan truck with a 2.4L engine. I recently re-built the engine and replaced the exhaust manifold (cracked) with a Pacesetter header. The exhaust gets extremely hot and the header glows red. I found a leaking fuel line back by the tank and replaced it (thinking that a decrease in fuel pressure/volume was causing the engine to run lean). The fuel line repair did not change the exhaust overheating condition. I plan on borrowing a friends fuel pressure tester and check the fuel pressure. If the fuel pressure checks out ok, how do I go about making the fuel injected engine run less lean?
Is the coil output enough to burn all the fuel? If not, the unburned fuel may be re-igniting in the header due to the heat causing the header to glow.
 

Just a thought; Did the headers come with a port for the O2 sensor?
 

The header did come with a port for the O2 sensor and EGR tube. A new O2 sensor was installed and the EGR tube was re-connected after the re-build.