HELP! major hesitation problems.
 

whenever i apply the throttle, the engine hesitates/stutters badly until the rpms go up a few thousand. my tps is set, and i cant find any vac leaks. i sprayed starter fluid around the manifolds and stuff, everywhere where i thought there could be a vac leak. vacuum at idle (1300 rpm) is 19 in/hg. could this be a grounding problem? clogged primary?

that's what I would do first, clean up the ground connections, especially the one on the top of the rear rotor housing...getting any codes?

i checked all the grounds, they seemed good. the problems started after i removed the rats nest and simplified the vac lines. i also had removed the lower manifold, and reused the old gasket with gasket sealer.

I don't see a problem with reusing the gasket, hell I've done it more than once myself, as long as you don't have a leak...first thing that comes to mind: did you route the vac lines back correctly?, and second: are you sure you regrounded that terminal good? you would have had to remove the bolt securing it to remove the rat's nest...if ya want, read out pins 3A & 3G from the ECU to ground ('86-88) to see if it's any good or not...

Mine used to do that. Mine was just running too lean at low RPM. After adding some more fuel down low, the problem was gone.

i dont have a fuel controller though, and i replaced the fuel filter to see if it would help, but it didnt. could it possibly be dirty primaries then? i used slightly smaller diameter fuel lines though. now that i think of it, i was cleaning the secondary fuel rail, and i blew it out with some air, could that have damaged the regulator? i wouldnt think it would affect anything though, as it runs fine after the rpms get up to about 2-3k

^

Using test lights or voltage at idle readings will get your idle setting perfect, but you could still have a worn out TPS resistor.
-The golden test:
Pull the TPS connector off.
Get an analog (needle type) VOM set to the 1K scale.
Connect it to the pins for the orange & green wires.
Open the throttle enough so you can test the TPS plunger through its full stroke.
As you work the TPS plunger in & out, the meter needle must swing smoothly from ~0 to ~5K ohms.

As the TPS wears, it can give non-linear or inconsistent signals to the ECU.
A worn out TPS may give 1K ohms at idle, but have a drop out or short further up the scale.
A drop out at mid scale will tell the ECU to idle at that point & give a fuel cut hesitation.
I had one go open at the top which made the S5 ECU go nuts, giving random fuel cuts.

i checked the tps, and couldnt find any dead spots.