1997 F150 4x4 5.4L Headers Flowmaster AirRaidIntake TowingCam 4.55Gears
My mechanic says I need a bigger fuel pump and adjustable press regulator. I need a recommendation on size and make of pump & regulator. What about injectors? What size are the stock ones? Should I get bigger? The truck dyno'd at 210hp at the rear wheels and the tech said it probably has 290hp at the flywheel. Thanks for any advise

 

Did he say why he thinks it needs more fuel? Does it run well?
Most towing cams are pretty mild, the intake and exhaust will lean out the mixture but if no codes pop up, it runs well etc I wonder if more fuel will help. Did he monitor the O2s? I think that the stock system can probably keep up with the mods but if the O2s show otherwise then maybe more fuel would be neccessary.

 

3 weeks ago I was towing horses up a long steep grade at 4000rpm in 2nd for over 5 minutes. After starting down the other side I noticed the checkengine light was on. The code was P1131 (HO2S indicates lean). It went off after the truck sat unused for 3 days. Last week at full throttle thru 1st then 2nd up to 4500 just as it was gonna shift it cut out completely like the key turned off (out of fuel?). I let up to half throttle and the engine was running perfect at about 3000 in 3rd. Felt strong like nothing happened. This Schneider cam makes a rough rolling idle but the engine jumps with no hesitation when stepped on. Will pump & regulator help or do I need bigger injectors?

 

Did he rule out other problems such as a bad MAF, bad O2 etc?
The stock system should be able to compensate unless you have a pretty radical cam, very free flowing exhaust, ported heads etc.
The stock pump should be able to put out enough volume and pressure to keep the engine happy, if it's working properly. A new regulator could be used to richen up the mixture a bit and would certainly be an easier and cheaper thing to try than injectors.
I've also asked Eric Brooks to have a look at your question. He has lots of experience with modified Mustangs and may have better answers than I do.

 

18 months ago (before all the mods) I was towing horses home and the truck suddenly ran like crap and the checkengine light came on. Took it to Ford and they replaced the MAF. Is there a test to see if the MAF is actually up to specs?

 

Yes it can be monitored with a scan tool.
You can also just try cleaning it and see if that helps. There are numerous posts on here about doing that, including in the Frequently Asked Questions at the top of this forum.