So it finally happened after 26 years and 130K miles my T100 3.4v6 finally through me a check engine light. I hooked up a OBD2 scanner and pulled the following codes. P0450 and candidate P0441. The P0450 is sensor for emissions. It measures vacuum or pressure on vacuum line. Toyota no longer makes the part needed but with some mods a Duralast MAP Sensor SU4197 will work as replacement. The P0441 is Purge Valve also part of emissions package. Toyota does not make this part but Duralast Canister Purge Valve PV421 will work in its place. So next steps is going to be check all vacuum lines and replace any cracked or split lines. I will likely purchase the MAP Sensor and replace it. I will then clear codes and run truck for a while. If I get the check engine light again or candidate code P0441 I will replace the Purge Valve. Guess what I am doing this weekend.