I'm going to install the in-tank pump (hopefully this weekend) and expect that it will resolve the half-tank-left-turn pickup problem. I'm hoping it fixes an intermittent power hiccup that I've been having at high RPMs. Generally between 4,500 and 5,500 RPMs the engine will just miss beat. It happens about once a lap and at random intervals. I've not watched the AFR gauge at precisely the time of the hiccup, but in general the ratio is in an acceptable range.

Should I be looking at anything other than the fuel pump? (Obviously, there is a world of electrical gremlins that might explain it, but I've been through the alternator wires and did the "juggling the relays" tests.) Mostly I'm wondering if the fuel volume problem could create the hiccups.

I had a similar problem last year. Drove me nuts because it only happened at speed at WOT - like you. Threw a bunch of the usual parts at the car (relays, injectors, plug wires, etc. etc. etc.) Then one day I was looking at my data and noticed that the voltage had been sliding down slowly over the past few months. Rebuilt the alternator and bingo the mysterious gremlin was gone. YMMV

We had a fairly similar problem that seemed to be the crank sensor

Is the crank sensor an SCCA / Spec part or are off-the-shelf Escort sensors allowed? For a $15 part (off-the-shelf) it's cheaper than a refill of motor oil!

Crank sensor is a Ford part. Do check your data (if you can) and verify that the voltage is above 12 v. Werid things happen in the ECU when the voltage drops. If it gets tool low the fuel pressrure will fall off as well.

Jerry A. wrote:Then one day I was looking at my data and noticed that the voltage had been sliding down slowly over the past few months. Rebuilt the alternator and bingo the mysterious gremlin was gone. YMMV

Voltmeter reads a steady 13.6-13.7 at higher revs (sitting still) so I'm doubtful that it's an alternator problem. I may "borrow" a rebuilt in any event to see if it changes things. Unfortunately, my neighborhood is not conducive to full throttle, third gear test runs! All I can do is try stuff and hope it clears up the issue.

I had a similar thing happen at NJMP several years ago, and it turned out to be one of the relays. It happened quite suddenly like you describe...