Intermittent Starter Problem
 

I have a stock 2005 roadster with automatic transmission. It was handed down to me three years ago by a family member who was the original owner. It has been a joy to drive but I only use it when I am in FL for the winters and each year it seems to have a service issue when I fire it up for the new season. This forum has a been a huge help in dealing with past problems (and some likely future ones). This year the issue is intermittent starting. When I turn the key to the start position the engine will usually activate the starter and crank for about a second and then stop. But, sometimes it will not engage the starter at all and other times it will just start like it should. On the occasions when it does not start I have waited for 30 seconds to see if the fan starts running and it does not. I pulled the 2 year old battery and had it load tested and checked for full charge and it seems to be fine. Before reinstalling it I cleaned the posts and the battery cable terminals. After reading a lot of great posts in the forum I have convinced myself that the problem is likely to be the RCM or the PCM or the transmission Park/Neutral switch.I had the transmission worked on last year because the sensor port was leaking so I figure that could have disturbed the linkage or the switch mechanism. If anyone has ideas on how I can narrow the list of suspects before I start replacing parts, or a rationale for prioritizing replacements, I would appreciate it. Or, if I am missing a likely candidate, that would be good to know, too. Thanks!