Turbo M20 hard stutter under accel

[turbski]

Changed the plugs out yesterday. Ngk bpr7es. Gapped to .023" made a difference in idle but not much else.
next step is a test light and will probably pull and inspect in tank low pressure pump.

[turbski]

Just spit balling.... Doesent ms2pnp have 4 led lights on the outside of the box? 1 of which being power to coils?
I'll look it up but might be an option diagnostics wise

[TobyB]

oh. Change to a BP7ES. Get the resistor out.

Misfires show up as lean spikes, as Davie says, because the sensor's reading oxygen, which is pumped through when a cylinder misfires.

You say 'wasted spark' but there are a lot more parts to the ignition system than that- which coils, wires, how are they supplied with power?

Like Varg and others, I've experienced spark 'blowout' under heavy load, and it feels like what you describe. Resistor wires combined with
resistor plugs and a resistor rotor did it, in my case.

Alternately, a 100psi pressure sensor is $15 on ePay, and plumbed into your fuel system and logged, it will rule out
any fuel delivery issues, which can ALSO give you a stutter under full load- we had a problem with cellulosic fiber
from a failing fuel cell, and I SWORE it was an ignition misfire right up until they showed me the furrball that
used to be the fuel filter.

t