Interesting idea. IDK how to do that, do you? I'd only do short term as a test. Since driving like that too long, would likely overheat pump further.
"Manifold Temp" Are you meaning cylinder hard temps?
One other thing may be to pinch off return line. This increase fuel pressure in rails. If RPMs go up, it's a clue of low fuel pressure. Which is likely fuel pump and or fuel pressure regulator issue(s).
But usually with these 06-07 fuel pumps. That by just engine shutting down (stalling) and waiting a few minutes. They fire back up. So we tend to just drive without further ado!
I've one now we're trying to get ECT (engine coolant temp) down. One thing we're going to try is a new fuel pump. It had a crank no start, after a heat soak (boiling fuel). It's possible it's running lean at times due to heat soak and high outside air temp (OAT). Thinking is, heat increasing resistance in wiring and pump motor. The shutting down, may be clue of a bad fuel pump during heat soak. Slowing flow and pressure of fuel delivery to rails/injectors. Causing a lean running condition (hot cylinder head temps). Also fuel heating, may also reduce fuel delivery to cylinders, as molecules expand. Also adding to lean condition.
I did run pump by cranking engine with fuel line off filter. But it was not a heat soaked condition. I didn't measure volume either and didn't have issue with that fuel pump. It was on the
Unicron. I now know, why it had gunk buildup at fuel hatch door. Engine CAT were overheating and thus so was fuel. I found the radiator fins badly clogged and suspect coolant was low for a long time (20K miles in one year). Engine got so hot, hoses disclosed and plastic melted, even the block was disclosed. I now know the gunk under the fuel hatch door, was sign of fuel boiling. Once I had it all back together. I test drove, it had no fuel pump (factory pump) issues or and any other.
But today I've a better understanding of the fuel pump issue in 06-07. As such I'm inclined to recommended replacement of fuel pump proactively.
What I see as they heat up, from running in it's high speed (engine pulling vehicle up a hill does this) typically on a hot day. They fail and engine shuts down, as pump relay drops power to pump for lower RPM low pump speed. It's not the relay but the pump itself that fails.
Wire starting at battery post and grounds, I do feel have effect. After all, corrosion and age increase resistance, reducing AMPs to fuel pump. So age certainly is a factor.
But my first experience with these 06-07 fuel pump issue, was in
Snowy when brand new. PO (one owner) had complained from mile ~1. Toyota Dealership tested and tested, again and again over next 95K miles. Even had pressure gauge and tech stream hooked up and w/service manager, shop froman and mechanic (master) in the vehicle. Drove to into mountains to recreate and could not find any issues. They keep testing fuel pump time and time again. Finally for some reason, they just tossed in a new fuel pump. History showed the next 100K mile after new pump installed, and AFASIK, still works today without issue.
I'm convinced the factory pump in the 06-07 which is a smaller Denso than past (98-05 Denso and Aisin fuel pumps) years, has a defect. They get hot and resistance builds, pump slows, and then engine runs lean. Often stalling as pump switch back to low speed VIA relay reducing volts/AMP. Put in a new fuel pump and cleaning up battery post/cables/wire block and all works fine. Just pump resolves issue. But one's asking for issue, if battery area and grounds not serviced also.
To test pressure of these fuel pumps, is usually not going to be revealing. The best test is in real word on a hot summer day.
It's not a bad idea. But you can wait until first time you've a shut down.
Few tip when replacing fuel pump:
Relieve fuel pressure, by disconnecting wire block under DS passaged door and frame rail, crank engine, disconnect battery.
Hose off top of gas tank, once body access hatch under seat removed.
Replace tank seal at top of pump assembly.
I wrapped my fuel lines with heat wrap, specifically where they go by the cat and it seemed to fix the boiling in my ‘06. It’s a crap shoot, many different attempts … no definitive fix.
