'94 Multiple Trouble Codes at once

I've been having some issues with my Buick stumbling lately, but it's an intermittent problem. Often, it will miss or stumble in the first five minutes of driving, but then run perfectly fine. It has also occasionally "hiccuped" while driving at a steady speed on the highway, but it's been getting worse.

Today, I was driving it with the code reader attached, and it actually cut off twice while I was driving and spit out three trouble codes all at once:

P0321 Ignition System Problem: 18x Interrupts Lost Signal
P0341 Ignition System Problem: Camshaft Sensor Intermittent Signal
P0361 Ignition System Problem: Electronic Spark Timing: EST Not Toggling

I've had to replace the main computer module in this car at least three times at this point. Previously, the sign that the computer was dying was spitting out a lot of trouble codes at once. Does this seem like a cluster of trouble codes that could all happen at once and then magically fix themselves, or is it time for another computer module?

The car runs perfectly, acts up briefly, and then starts running perfectly again.

Looking at all three codes, the ICM is common to all three......check the harness into it, that all female connectors are tight...

Could be the ECM/PCM too.......try a tap test on it?

I unscrewed the ICM connector this morning and sprayed DeOxit D5 on all the contacts. One of the stalls happened after I did this. Perhaps after 160k miles the ICM's active electronics are starting to go.

Are there any diagnostic tips/tricks that might give me a better idea of whether the problem is in the ICM or the ECM?

The only problem that occurs regularly is that it stumbles about 2-3 minutes after a cold start, then runs fine once past that. This doesn't cause a trouble code to set.

The stalling out is very intermittent.

I tried tapping the ICM and moving the wiring harness with the car warmed up and running. No effect.

Try tapping the "top" of the ECM/PCM......

Rhodesplyr,

I am curious as to what "coder reader" you are using? I have a 1995 LeSabre and anything other than a GM Tech 2 has trouble retrieving codes. The OBD on my vehicle is sometimes referred to as an OBD 1.5. Here is a link to some more information on this issue: http://www.automotiveforums.com/t307153-new_info_1995_non_obd_ii_16_pin.html.

Thank you in advance.

All I can report now is that the problem has gone away by itself. It's been a week since any of these problems occurred.

I am glad that everything has worked out, I was just wondering what type of "code reader" (Manufacturer and Model No.) you used. From past experience, the only scanner that seems to work on my 1995 LeSabre is a GM Tech 2, which is expensive and difficult for me to get ahold of.

Perhaps the type of "code reader" you used, might work on my vehicle.

Thank you again in advance.