Intermittent Stumble Ford 2.3L Turbo

[gman]

1987 Ford T-bird, logged on MS2 when going through the first three gears. When in second gear, around 5565 rpm, the engine bucked. The log shows Duty Cycle / PW dropping to zero at the transient, as if the squirt just decided not to squirt, then continued on its merry way. After shifting to third gear, that pull was fine.

I'm just wondering if anyone can help guide me what I should be looking into to rid myself of this issue?
I've changed FPR and fuel pump, and on the ignition side, plugs & wires.

Thanks,

Rob

[72bluetr6]

You did not get the stumble in first gear and did not reach 5500 RPM in third gear. Do you get it only in second- and is it repeatable?

[billr]

I'm thinking the fuel PW was cut because the rpm was suddenly rising at 50K+ per second, MS predicted that the rev-limit was going to be grossly exceeded, rapidly. The question is... why that spike in rpm?

[slow_hemi6]

I would say the rpm spike triggered the limiter but it just happened in between reads of the logger.

[gman]

You did not get the stumble in first gear and did not reach 5500 RPM in third gear. Do you get it only in second- and is it repeatable?

It's not repeatable -- it's intermittent, and I can't legally reach 5500 rpm in third gear. Sometime I get it at lower rpm in higher gears.

[gman]

Thanks everyone for your posts. I swapped the dizzy, figuring it might be the PIP or TFI. Looks like the problem went away.