2000 Chevrolet Suburban 248,000 miles
Our Suburban recently started dying/losing power while driving generally at speeds under 30 mph. Checked the fuel pressure regulator and it was leaking fuel into the vacuum line, so replaced that. Also replaced the fuel filter. Checked the EGR and it appears to be working(button moves freely), cleaned the carbon deposits and replaced the seal. Immediately following these repairs the fuel pump was running loud and continuously at idle and when driving. Vehicle idles fine and we are not experiencing the dying/losing power we were previously. Checked the fuel pressure by just turning the key in the on position, fuel pump turns on and reaches the correct pressure immediately then slowly loses pressure. When the vehicle is started it reaches the correct pressure but needle fluctuates all the while the fuel pump seems to be working really hard to maintain pressure.
Codes pulled indicated EGR valve stuck open, but with cleaning and new seal it appears to be working correctly.
Any ideas on what to look for next?