98 K2500 Suburban Timing Question

I have a 1998 Chevy K2500 Suburban 454 (7.4L) with 108000 miles. I have been working on (what I believe to be ) some ignition issues. Originally it
would cut out briefly when going up a hill under 30 mph -- more pronounced when towing. No SES and no codes.
I decided to replace the spark plugs and wires (with AC 41-933 plugs) and a set of Belden wires from NAPA. Before changing the plugs and wires, I connected my scan tool (OBDII from carcode.com) to capture some data. I noticed misfires mostly on cyl 7 and occassionally cyl 4 & 6. But what really caught my attention was the Camshaft Retard (CMPR) which varies between 4094.14 and 4095 degrees. I looked over the timing adjustment procedure in my factory service manual -- but I doubt it would correct that big of an offset.
After changing the plugs and wires - it doesn't cut out like it did but the CMPR data is still the same. Misfires are now primarily on cyl 7. Again, no check engine light or codes. Other symtoms include a slightly rough idle, lack of power (more noticeable when towing), and knocking.
I am trying to decide if the Camshaft Position Sensor is bad or if the scan tool is giving me bad data. All of the other data values from the scan tool appear to be within range.
If the CMPR data is correct - wouldn't it be running a lot worse than it is ? Anyone see a similar situation where the CMPR was this large ?
My next step would be to replace the Camshaft Position Sensor - but I wanted to get some other thoughts on this first.
Thanks, Chuck
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The scan tool is giving bad data. There is no such thing as 4095 degrees of cam sensor offset.

And it would be setting codes.

Yup, it was an acknowledged software bug.

Get a genuine Delco cap and rotor. If the miss is still there after that, I'd look for a stuck injector poppet on #7.
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Thanks. That was the sanity check I was looking for. I contacted to maker of the scan tool and he confirmed that the scan tool was interpreting the negative values for the CMPR incorrectly. He provided an updated version of the tool that now shows my CMPR between -1.1 and -1.7 degrees. So, I don't have a timing problem it appears.
My scan yesterday still showed misfires on #4 and #6 in addition to #7. I am going to replace the cap and rotor next.
Thanks for your help.
wrote:

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