In that case it's looking like it's not ignition related, in which case it must be injection related. So the next test I'd recommend I've never actually had to do but should tell you a lot. Google injector noid light test. Basically an LED light is wired in with the injector and will flash with the injector pulse. If the injectors are not firing at that rpm then the LED light will stop flashing. This only works with a rather specific LED bulb, a normal test light will not work. Only LEDs flash fast enough while only needing a small amount of electricity.

 

what was the timing set at and did you pull the spout connector prior to checking the timing?

 

I've heard of this actually. It's a pretty old trick in the fact that my dad used to do it. I don't know how well it works since I don't use EFI but it's worth a shot.

 

so heres the scoop guys I did the noid light test and as far as the electrical part of the injectors them are fine I don't no why I didn't check the injectors them selves before hand I guess I just didn't think it was fuel related and maybe im getting ahead of myself but I went ahead and pulled a few of the injectors and you would not beleave the crap that came out of them rust dirt grime it was awful so I have 8 brand new accel injectors that I had from another project im gona put them in tomorrow or first thing sat morning I will let you guys no what happens I hope the injectors are the problem

 

Maybe b4 you think about puttin brand new injectors in you should think about cleanin the fuel tank and lines to get rid of the "rust,dirt and grime" you describe.

 

Orrrr, do both at the same time! You know, 2 birds with one stone?

 

its got a brand new fuel tank from this winter thinking of that is what maid me think of the injectors the tank leaked bad when I got it it was all rotted and completely out of gas and had been sitting for 4 or 5 months I don't have a dime invested in the new injectors so why not try it I plan to blow out the lines when I remove the rail

 

so I cleaned the fuel lines and replaced the fuel filter again put the brand new injectors in same problem im out of ideas and parts to replace well free ones anyway thank you guys for all your help and suggestions

 

I hate to say this but I think your down to the ECM, it's the last thing I can think of that could cause such a RPM dependent problem.

It does do the same thing at the same rpm both under load and revving in the driveway right?

 

yes I can make it do it at any point in time in or out of gear at 3500 rpms and when you say ecu your talking about the one bolted into the fire wall on the driver side?

 

I don't know S**T about EFI stuff but a quick googling says it's the computer. The ECU I mean. Which is not very cheap. Soo, hit up the local junkyards, find one for $20 or 5 finger discount and plug it in. See if that helps.

 

I changed it already about a week ago it didn't help

 

did you ever unbolt your y pipe to make sure its not a clogged cat converter.

 

I didn't figure there was a need to as there both hollowed out

 

So we know it's not fuel related? And we know it's not spark related?

Does the temperature of the engine have any effect on the rpm at which it cuts out?
Do an oil change lately?
Did you by change put in a thick oil?
Have an accurate oil pressure gauge, not the stock Ford one?

My reason for asking, I have seen once an engine where the oil pressure bypass stuck closed. This caused the oil pressure to spike causing the hydraulic lifters to pump up holding the valves open.

It's a shot in the dark but we're grasping at straws here.