What's my problem?

[Stephen Soulsby]

After much frustration in tracking down the stumble and very bad idle, I borrowed a Snap-On computer scanner. When I forst hooked it up the MAF numbers were jumping anywhere between 8 and 225 at idle. The O2 was also jumping from 75 to 1050 at idle. Also the scanner said the motor had 9-12 degrees of knock retard just idling. This is all with the stock prom chip. I swapped in a Posten 93 chip I had for the car. After that the MAF readings were steady at 6 during idle and knock retard want to 0 at idle. RPM was still jumping between 700 and 850 erratically and the O2 volts were still just as jumpy. The O2 sensor is about 5 months old, but I will change it tomorrow just in case. What is weird is when I disconnect the O2 sensor the scanner still gets jumpy O2 voltage, but not as much voltage. All other numbers check out good I think. TPS is .44 at idle and 4.72 at WOT. IAC is at about 40 at idle and around 60 in gear, but it does jump around somewimes. The IAC is new and I followed the reset procedure on GNTType.org.

I put new bearings, gaskets, high volume oil pump and lifters in the motor about 2,000 miles ago. I'm wondering if I maybe have a wiped cam lobe? What are the symptoms?

Thanks in advance.