i have a 99 v10 with 290,000 and its always run good ,now it will idle fine with 30 lbs of pressure at the rail ,but falls to nothing at wot .
replaced all plugs and cops ,throttle pos.sencers,fuel pressure reg.,fuel filter,2 02 sen. and fuel treatment ...still will idle great but no power any ideas .

DRIVING ME CRAZY

 

fuel pump dieing ????

 

the ford dealer told me that the pump either works or it don't work ,he said it was like a light switch ..off or on ..i just changed the relay for the fuel pump and nothing ,not even revving like it did before ,but what else could it be ? I guess the tank comes down and see if the pump is clogged or? and replace it anyway.

 

Fuel pressure regulator, vacuum controlled. Just throwing out an idea.

 

I had a similar problem with my 99 V10 a couple of years ago. Sort of normal pressure at idle and low pressure under load. Mine was also kind of intermittent. Gas tank had fair amount of dirt floating around in it and fuel pump socks looked kind of clogged. Cleaned out tank and replaced fuel pump, it's been good ever since.

 

I say it is the fuel pump. Just when you make absolute rules about something that is when you get the exception.

 

I had a fuel pressure problem with my 94 which used the same style of fuel injection. The problem ended up being a combination of a stuck fuel pressure regulator and a weak fuel pump. Once the fpr was replaced, the truck still ran on that pump, but the pressure was too low. Not sure what was wrong with the pump to cause low pressure, but replacing it solved the issue.

Also a good suggestion to check the vacuum at the fpr.

 

Most of the time, yes.
BUT, they eventually do wear out. I am pretty sure these are vane style pumps. Very reliable and long lasting, but they do eventually wear and slowly put out less and less volume per unit of time. It sounds like this dealer rarely sees truly high mileage vehicles....

I see you already did the FPR.
If it were mine, I would give her a gift of a new pump, prefilter sock, and clean out the tank. 290K means a LOT of fuel pumped in there from all kinds of storage tanks... I'd be surprised if there wasn't quite a bit of crud accumulated in there.

Show her some love - she's earned it.

I'd give it at least 60% chance of solving the problem.

After that, It's time to look for partial blockages. Pinched fuel line? Crud puilt up somewhere?

 

wow she runs like a nascar now thats what a v10 feels like .
I changed the fuel pump and cleaned the tank and she is better than it ever has been since i've owned it .
Thanks for all the help guys she has 294,590 miles on she is back to life to hopefully go for 100,000 more


BUILT FORD TUFF

 

Thanks for the feedback.

 

Ok so my 04 with just under 100k had 16, no power at all, just replaced the maf fuel pump and fuel filter, a whooping 22 at wot and 24 at idle...

 

What about your fuel pump relay? Check fuel pressure regulator?

 

I'll have to check, take vaccumm away and see if pressure goes up? What Bout the relay?

 

Did you replace the relay?

 

No!? I was supposed too? Where is she located?