Fuel pressure swinging from 60-100 psi??

[Cowboy Cadillac]

On the drive in this morning I noticed my fuel pressure guage (added) seemed to be reading 100 psi. The next stop light I got to I shut the truck down and restarted it and it came back to 60 psi where it normaly stays. Thoughout the rest of the drive in the pressure would swing form 60-100 and seemed to be some what associated with the position of the skinny pedal on the right. It was a little cold here this morning (18 F) and was wondering if that may be what is causing the swing or could this be a sign of an up comming problem?

Any suggestions welcome,
Thanks in advance.

[smokersteve]

It could have been a fluke.

BUT the fuel psi should never pass 65psi. I have been told that there will be nasty injector leaks once you pass ~70psi.

[blackshadow]

You might want to check the sending unit.

[zooterboy]

Mine does that sometime too, however it dont get that high. I sits at 60psi 99% of the time and when I stop for a long time and idle it will creep up to 68 and when I start driving again it goes back down. only does it once in awhile when its cold out. So I'm not too concerened about it.

[bondsman]

Are you running a regulated return? Stock fuel system? If it is a regulated return, make sure you don't have that boost line hooked up to the regulator. If it is the stock system, your regulator spring or popet could be sticking.

[SickStroke6.0]

You may need a new fuel pressure spring.

[wetnsloppy4x]

A worn regulator spring would more than likely yield low pressure unless somehow something has come apart and the check ball and spring are plugging things up. I don't think thats a very likely scenario.

This sounds like a sending unit issue.

Where is the unit mounted? If it's not isolated from the engine via ss braided line, heat and vibration will kill the sending unit fairly quick.

[Cowboy Cadillac]

Hey, Thanks for all the suggestions. Any idea on how I would go about checking these things. I did not install the guage. It was on the truck when i bought it.

[bismic]

There are components in the regulator (other than the spring) that could stick and cause high pressures.

Fords upper limit is 75 psig.

[wetnsloppy4x]

Originally Posted by bismic

There are components in the regulator (other than the spring) that could stick and cause high pressures.

Fords upper limit is 75 psig.

True. I didn't mean to sound like the regulator couldn't be the culprit.

Sorry, I don't have any pics of the fuel bowl handy to show what to look for.