Fuel Pressure Drop 99 GT


Active Member
Nov 20, 2018
Dayton, Ohio
Let me first list my mods because my car is far from stock. BTW my mustang is a returnless fuel system, which also means NO regulator. No codes either.

Forged Internals "pistons, rods and crank"
Compression 10.8
Bored .020
Trickflow Twisted heads "ported"
Typhoon Intake"ported"
Stage 3 comp cams
47lb Ford racing injectors
Eldelbrock fuel rails
Cold Air intake
Plenum and Throttle body
260 lph SVT Ford Focus pump

I literally have less than 300 miles on vehicle and just got it back from the rebuilder.

The datalog is attached for viewing. I've struggled to get everything perfect since I believe my fuel pump might be going out. Its a newer pump but the issue remains. Pump probably has less than 1k miles.

: Bucks when WOT between 2nd and 3rd gear.
Pulls strong any other time and pressure remains constant in any other gear.

FRP drops to 8 from 38/40 when the issue arises.
FPDC drops to .05 from average of 24

Again datalog is attached. The issue arise's at 3 minutes 28 seconds in the log. I haven't checked anything yet and wanted solid advice before starting my troubleshooting. I would love to know what setup I should use or others are using for a fuel pump on a returnless system.


  • datalog4 STFT Cut Out Issue.zip
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