Here is a summary of my experience for others who may face this same problem.
The problem appears to be the contacts. The ones I removed are indeed worn and at least after doing the replacement the car has started successfully twice.
The job was alittle mroe difficult than I thought it would be. The starter is mounted with two bolts and the head on the top bolt was a blind operation which made it difficult. Access to the lower bolt was not that great either but at least I could see the head. Clearance around both bolts was minimal, no room for fingers and when I got a rachet or wrench on the head the swing was minimal so it took a long time getting the bolts out and back in. Removing the 12V low current control wire was also difficult becauser there was some locking mechanism on the connector and while it was fairly obvious how it needed to move it was not easy to do. I had thought about the possibility of replacing the contacts without dropping the starter but after looking at that it would have been very difficult to do. I purchased the contact and plunger by finding the part on the following web page:
http://www.partsamerica.com/ProductDetail.aspx?MfrCode=VLP&MfrPartNumber=ND34SOL
The price on the web page was $12.99 but when I go to the store that had it (only one of five stores in my area had it in stock) it was $17, I guess I should have paid for it on the web and done a store pick up! I did find a auto electric repair shop that would sell me just the contacts for $7.50, but they wanted me to bring in the old contacts so they could match them and I didn't want the vehicle disabled during that exercise. I did find a rebuilt starter at Advanced Parts that claimed to be a Nippondenso original that was rebuilt in Mexico, but it cost $109.
The job took about two hours. Lots of lying on the garage floor and getting up and down because you needed to be under the car and then over the top of the radiator frequently, especially when puttin gthe starter back in palce and getting the top bolt started.
Thanks to everyone who provided some insight on this problem! I hope my comments will be useful to someone in the future.
John Keith