jumping tach and engine cutout

93 RMW, 5.7, The tach in my Roadie is constantly jittering and every now and then it feels like the engine momentarily cuts out. It seems to idle and run smooth in general for a 225k car. I've replaced all the sensors except the crank position sensor. I've replaced the egr valve and did a major ignition tune up including the module(and the grease). It ran great for a couple of months. I've also cleaned the ground strap from the engine to the body. Do you think the two symptoms are related? Could it be a faulty NEW module? Is the "cut out" I feel actually an indecisive transmission? Seems more ignition related all around to me......HMMMMMMMMMM

Thanks!

Have you done plugs, wires, cap and rotor with delco parts? Also, check your vac lines make sure you didn't break or knock anything off.

First of all, you do not use dialectric grease, you use heat sink compound found at an electronics store like radio shack, for the module. Did you set your timing with the tach connector disconnected (on the PS valve cover)? Did you properly reconnect the tach connector? You could check the ground at the thermostat...make sure the bolt and threaded hole are clean (do when the engine is cold) and clean the lugs. It is the ground for the ECM and O2 sensor. Is your distributor tight? The wires at the ignition module on the distributor could be bare. I had that happen to me on a 90K car. Heat will make the insulation brittle and it will fall off. Then the obvious will happen...the wires touch, and wa-la ignition problems. Check the connector for the module in the distributor for cracking, I had every one break that I have disconnected. I hope I have given you some food for thought.

Since your Tach is talking to you do what Fred said to do.After my complete tuneup my engine
ran great but my tach was reading close to twice what the engine was actually turning.This
was found by using my antique code reader called a Monitor 4000 Enhanced from OTC. Any
way make sure your connections at the distributor housing on the drivers side.
IMHO
Jim Gordon