car is throwing P0231 and P0353 codes, need some help

mineralgrey01gt

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My 2004 mustang gt is throwing these 2 codes. I know the code P0231 is a fuel pump relay problem. Now the car has a complete fuel system from Glenn's Performance with a sleeper tank and twin 300lph fuel pumps from walbro and each pump feeds each side of the engine. I found a relay for the system that one wire is tied into the factory system. Could this relay be the problem? The pumps do turn on and pump fuel, it has around 25psi of fuel pressure which seems right im assuming. If the relay was bad the pumps wouldnt turn on right? If 25psi is low could that cause the P0353 code to throw? Also could dirty fuel injectors cause that problem? We changed the coils around and the code stayed on that same cylinder. The spark plug was good, I am getting full voltage through the coil.

Back story on the car: It sat up for 5 years with the intake off of it but engine was sealed up very well. The engine and heads are fine on the engine, we changed all gaskets and seals on the engine. The injectors were left in the intake so thats why I mentioned a dirty injector problem. It slipped my mind to clean them before they were put back on. I cleaned the fuel tank, fuel pumps, etc. Transmission was flushed and is working properly, rear end was flush and is working properly.

Im leaning towards dirty injectors or a bad PCM. Any thoughts would be appreciated!
 

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