occasional sputtering or hesitating under WOT at high RPMs

[General Geoff]

It almost seems like air or sediment in the fuel lines. There's no CEL, not even momentarily, and this seems to only occur when I'm low on fuel (gauge indicates 1/4 tank or less). Is it possible that the fuel is sloshing around enough under hard acceleration/shifting that the fuel pump is pulling pockets of air? Everything else on the car runs great. I was testing the theory this evening when the low fuel light came on, so I did a couple of WOT runs up a moderate grade hill. Each time past about 5000rpm, it would hesitate/sputter for up to a half-second, intermittently. I don't recall this ever happening on a full tank, but I'll continue with my experiment hopefully tomorrow after I fill the car and see if I can duplicate the symptoms.

Anyone else have this problem?

 

[msteiny]

Sounds plausible to me. Just remember the fuel pump is cooled by the fuel in the tank, so spirited driving under a 1/4 could lead to a new pump. Not preaching here because we've all done it. You could try running a pressure gauge off the fuel rail and bring it into the car with you or tape it to the windshield (if you want to go the safe route) to check your theory.

 

[General Geoff]

Well, I filled the tank this morning, drove a mile to clear any air pockets that might be in the lines already, and then tried WOT up the same hill a couple of times. No sputtering or hesitating! I even tried WOT again about an hour later (commute to work is 50 miles), on a similar hill, still no sputtering or hesitating. Pulled smooth and strong all the way up to 7,000rpm.

So my theory appears to be holding true so far.

 

[msteiny]

Good.