my OTC tool is pretty comprehensive up till '99, and i found i can lie to it and go up to 2004 in some cases. there are no cartridge upgrades available, and for the last several years, i have been looking on and off for a newer tool. it does monitor many things in real time, and timing is one of them. i'll have to hook it up again and view the info presented, then write it down for the record. the PVC doesn't appear to be sticking, and there are air paths at the throttle body, some before the blade, and some after. i'll have to look again to see what is what there, and report back. we also checked the throttle body for any deposits on the back side of the blade, as well as the spring return and for any play in the shaft that might cause an air leak. everything was ship shape. thank you guys for your effort in trying to pin this down for us !