'85 Turbo Z - Bucking Like Mad

[ljeff20]

Here is what I have:

1985 Daytona Turbo Z
TII converted with donor parts from '88 Shelby Z
GLHS Stage II LM

A few days ago, I noticed it would randomly 'buck' while driving. The engine would cut out for a moment and it was violent enough to almost throw me into the steering wheel. The first couple days it was somewhat uncommon, happening four or five times in 150 miles of driving. However, now it's near constant and has made the car undriveable.

When it 'bucks', the tach jumps all over the place.
No codes thrown. (12, 55)
A few days before this problem started, the temperature gauge stopped working correctly. For some reason I believe it reads ambient temperature, but not engine temperature, as there is a slight reading on hot days and nothing on cooler days.

Attempted solutions:
Have cleaned and reinserted the LM plugs several times.
Have traced as many wires as I could to check for breaks/shorts.
Relocated MAP sensor under the hood.
Cleaned/regapped spark plugs.
Replaced distributor rotor.

Not sure what else to check. Any advice?

[turismolover22]

Tps sensor failure? If the car thinks the throttle isnt open itll kill the fuel. Any grounds you missing? Is your injector harness ground ok? Old harnesses have a knack for housong broken wires within the hard dry plastic. Check that, it could be weak or inop.

[knepppipes]

Tps sensor failure? If the car thinks the throttle isnt open itll kill the fuel. Any grounds you missing? Is your injector harness ground ok? Old harnesses have a knack for housong broken wires within the hard dry plastic. Check that, it could be weak or inop.

pick up in distributor.not rotor

[iangoround]

Hall Effect Pickup aka Distributor Ignition Pickup. The flat disk lookin thing with the two leads coming out of it, located under the distributor cap and rotor.

1985 was an oddball year, with a different distributor from the 1986 and up ones. I see you did a t2 conversion though. Just make sure you get the right pickup for whatever distributor you're running. If it is the original 1985 distributor, you want KEMParts #E120 from Rock Auto. If its 1986 or up, you want the Standard Motor Products LX125T from Rock Auto.

Of course, part numbers will vary at other places. Just make you whichever one you get has two plugs on it and is correct for your distributor.

[turismolover22]

If this is the same one from td i believe he swapped it already. I can swing over and check.