I had preset my AEM FPR at ~43psi with the vacuum hose disconnected. I went to do some high way runs for about 2 hours. NO NITROUS WAS USED. After 1 hour of hard driving, the fuel pressure drops to about ~32psi at WOT. My EGT went to about 1400F. I believe I hit 115mph several times. The car started to misfire and I was getting flashing MIL. I drove for another 30mins and stopped to borrow tools to adjust the AEM FPR. This was the only spark plug with the melted ground strap and chipped insulator. It's from cylinder number 4. Now my question....Why does the fuel pressure drop after driving around for 1 hour? Is it because the AEM FPR is junk?

 

1400F is not that bad, depending on where your EGT probe is located. What are you used to seeing?

And yes, if your fuel pressure is dropping after an hour of driving, then the fpr must be malfunctioning.

What code did the ecu store?

 

What about your idle pressure? is it still constant, or did it drop too?


What about your fuel pump? if the pump is on it's way out, it can cause some of the same symptoms.