On 11/24/2011 10:52 PM, stryped wrote:
I have the 1996 silverado 350. ...
... The problem was bucking but sometimes the truck would
run just fine. I had the ignition module checked at autozone. it
tested bad they said and i got a new one. However, the code came back
the next day.

What specific code?

....

Checking the ignition control module harness white wire with a
voltmeter on AC mode should yield "approximately"1.0 to 4.0 volts with
the engine cranking. It yielded 6.0 volts in my test. it says to check
the crankshaft sensor if the voltage is out of range. Backprobing this
sensor with a voltmeter on AC should result in "approximately" 5.0
volts. My test resulted in 3.9-4.0. The manual then says: "If a CKP
sensor signal is not present, replace the crankshaft position sensor."

Well, my voltage was out of the 'approximate" range, but a signal was
present.

It goes on to say if the ignition control module test and the
crankshaft position sensor tests are ok, to have the PCM checked at a
dealer.

This is my daily driver but the truck has 342,000 miles so I dont want
to spend to much at a dealer.

Where should I go from here? Replace the crankshaft position sensor? I
have read something about there being a "relearn" process that has to
be done by a dealer sometimes when replace ing this sensor? Could I
still drive it?

Have '98 and '99 -- the '98 had same problem. The PCM was the issue

The equivalent of the Windows BSOD test is to read the OBD code. W/ the
ignition key in the "II" position read the OBD. A code value of P06xx
where xx=one of the values 01 thru 10 is a critical failure of the PCM.
If you get one of those it's toast and nothing else will cause joy.

I've not done the testing specifically so can't comment on various
observed symptoms as compared to the nominal given. The intermittent
nature appears to be related to the PCM from my observation; the other
sensors basically go and are consistent instead of come-n-go.

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