Slightly Low Fuel Pressure

sneaky98gt

10 Year Member
Apr 23, 2008
2,387
144
114
NC State University
For whatever reason, I've noticed that my fuel pressure has dropped just a little bit lately. It used to make right on 30 at idle, and right on 40 at WOT or with the vacuum line pulled off. Now, it is making around 29 at idle, and 37-38 at WOT or with the vacuum line pulled.

So far, I don't think I've seen any ill effects from this. I have just a tiny bit of detonation at the very tip top of the RPM range (5900-6000 rpm), but I had that last summer when it was really hot as well. Currently, I don't think the fuel has anything to do with that; I'm pretty sure it's just the heat/humidity of central NC.

It seemed to have happened relatively quickly. I just noticed it last weekend, and it hasn't gone away.

What could cause something like this? I can't really imagine anything. I supposed the filter could need changing, but I wouldn't think the filter would cause low fuel pressure at idle with the vacuum line pulled off.

And so everyone knows, I'm worried about this because I'm about to make some pretty major changes/upgrades to the car, and I wanted it to be running 100% correctly beforehand so that I'd know how it should run when I finish with it.
 
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