Chrysler Repair: 93 concorde ignition problem intermittent, haynes manual, vacuum line

Question
Roland, my mistake it actually is a Haynes manual I have. I am trying to locate a vacuum pump to further diagnose the egr valve, but I still have my doubts about that. The needle in the egr moves smoothly under acceleration, and if I unplug the solenoid or the vacuum line to the egr transducer it begins to run very rough but idles smooth as pie with everything hooked up. I hesitate to think a mechanical part like this could be that intermittent, however I am certainly no expert and that is why I wrote to you! Also, I didn't mention before but this problem happens at nearly any speed. I have experienced it at idle in park as well as under load. When it happens under full throttle it generaly will "get past the problem" so to speak. It will just glitch for a second like someone shut off the key and then run fine. Also, this doesn't happen all the time, far from it. Maybe 2 out of every 20 times you drive it. Today when I remove the egr I will attempt to view all the passages for carbon but it is in a very hard spot to see right on the back of the engine and all.

You wouldn't lean more towards an electronic problem because it is so spotty, and at other times runs excellent?
Thanks!
Chris

P.S. one more question, does the egr operate under all rpm's and throttle conditions?
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Followup To
Question -
Roland I am diagnosing a family members 93 concorde with the 3.3 V6. Some times it runs fine, and then just bam, shuts off. It is hard to reproduce the problem as it seems to do it with it cold, warm, whatever. I did check the trouble codes though there is no check engine light. I got an EGR code 32 problem, however when following the Chilton manual to test the egr system everything checked fine. I then pulled the battery cable and checked it again. After driving around the block a couple times it shut down no less than 5 times, but no trouble code came up. It shuts down really quick, doesn't seem to be a fuel delivery problem. I was able to get it running again under full throttle and while driving it would stumble and surge and try and shut down. I noticed during those moments that the green "cruise" light would come on momentarily. Although a very broad diagnosis, I am thinking it is in the PCM, the auto shutdown relay, the throttle position sensor, or the crank positioning sensor. (basicly every electrical sensor I know about LOL) Can you give me someplace to start to try and diagnose this problem?
Thanks!
Answer -
Hi Chris,
I haven't been impressed with the Chilton manuals, but I don't know what tests they recommended. The Haynes manual is generally more reliable. I would still suspect the egr valve/solenoid/hoses assembly. Have you observed the stem for ease of movement. Revving between idle and 2000 rpm should result in quick movement stem in and out. If not, try lubing the stem with WD-40. There are other tests by means of a vacuum gauge are described in the Haynes I can share those with you if you like. The symptoms sure are synonymous with an egr problem. Perhaps it would be worth while removing the egr and checking the passageway to make sure it isn't clogged up.
Roland

Answer
Hi Chris,
When you take off the egr check its internal passageway for crud and use the slot on the stem to open and shut it and try blowing through it with the valve closed to test how well it seals. On the rest of the egr system just try probing with a flexible wire for any build up of crud in the pipes. Once the egr is "cleared" we can focus on ignition, pcm or other sensors. But it is difficult without any codes to center on a cause. The ignition coil pack is about the only part that isn't monitored (on the high voltage side of the coils) or you could have a problem that is not so severe as to be picked up by the PCM but yet to cause you to stall (flakey MAP sensor for example). So it may have to get more unreliable before the PCM will show a code. But let's see how the egr checks out visually/mechanically. The last resort is to put a diagnostic readout box on it (Chrysler DRB II) and observe the parameteres of all the components.
Roland