PCM Data Stream Freeze

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December 19th, 2007, 6:31 PM

sschnelle

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PCM Data Stream Freeze

I have a ’99 Astro AWD and for some time now (Years maybe) it seems to have a miss at times when it shifted into 4th and torque converter lock (bucks). Six months ago I got a PO341 (Camshaft Position Sensor Circuit Out of Range/Rationality). Research told me that that potential causes were: defective Cam Position Sensor or Crank Position Sensor, Distributor out of adjustment, or worn Timing Chain. I replaced the Crank Position Sensor first (Easiest I thought), no fix, and then the Cam Position Sensor (fixed it). Was good for several months, still had occasional miss/buck issue, but I was happy. About 2 months ago, it started to miss under acceleration before it warmed up. It seemed to be worse on damp mornings. I changed the Plugs, Wires, Cap and Rotor, and Coil. No improvement and it continued to get worse. Now it idles fine and seems to run good under hard acceleration. Anything in-between it misses bad, cold or warm and occasionally throws a PO 300 (Random Misfire Detected). I hooked up a scan tool and determined that the PCM data stream freezes off idle, except under hard acceleration. Sensors appear to function OK at idle and under hard acceleration. As a result, I replaced the PCM and the replacement does the same thing. Any ideas?

Thanks,

Steve