Crazy fuel pressure fluctuations..

My 04 GT that I just picked up is having some crazy fuel pressure fluctuations.. It's got a single Ford GT pump installed, and the car makes around 540whp with a built motor/t-trim.

I've noticed that while cruising around, from time to time, the fuel pressure gauge will start bouncing around wildly (back and forth), between 30 and 60psi of pressure. The car runs like crap and surges in tandem with what the gauge is doing. Usually, stepping into it past 1/2 throttle makes it stop.. but, it's getting worse and worse. Sometimes, pressure is at 30psi.. sometimes 40.. other times 60. I've never seen this happen before.. Anyone else have this issue?

Travis

It's definitely out of pump.. that's for sure. I purchased the car like this, so I'll be doing some upgrading for sure.

The previous owner ran a -6 feed line from a Mallory fuel filter (in the stock location), up to the fuel rails. It is pretty new (6K miles).. The pressure at idle is usually around 35-40psi, and once I'm crusing around, ranges between 50 and 60psi. The fluctuation starts usually after I've been driving around for a while, and usually in stop and go traffic. The gauge will start bouncing around, back and forth, between 30 and 60psi.. I've logged it all over the place with my Predator, so it's not the gauge. Stepping into the throttle, past 1/2 or so, makes it jump to 60psi, and it usually goes away.

The MAF is draw through.. and the recirculation is about 12" upstream from the MAF, with a 90* bend between. I will log the MAF though, and see what's up.

I plan on doing a new tank with twin supercar (GT) pumps, divorced, with an external "Y". Where can I get the upgraded wiring?



Travis

I'll have to look into going blow through.. I set up my last Mustang that way, and it ran great.

The wiring seems easy enough..

Travis