intake manifold service

The Classic Prius was highly subject to engine no-start issues (DTC P3190 and P3191) due to a dirty throttle body interior and throttle plate. The 2G Prius also will benefit from occasional cleaning of the throttle body interior and throttle plate to prevent those issues, although it is not as susceptible. The Prius throttle body interior does not have a coating that you need to be concerned about removing.

This is a very easy DIY activity. Remove the engine air filter housing for access to the throttle body. Then you can rotate the throttle plate by hand, and clean that off as well as the throttle body interior with a clean cloth that has some throttle body cleaner fluid sprayed on it. That method was suggested by Toyota in a TSB relating to engine no-starts. Do not drown the throttle body in cleaner fluid as that will encourage dirty fluid to drip down the throttle plate shaft into the throttle motor and potentially cause problems.

I use Q-tips soaked in isopropyl alcohol instead of throttle body cleaner on a cloth. That achieves the objective of using minimal cleaning chemicals and the IPA works well as a solvent.

If you decide to actually remove the throttle body from the intake manifold, then a new gasket should be installed to reduce the likelihood of an engine vacuum leak. Such removal is not necessary if all that is desired is to clean the throttle body interior.

 

Old thread....Brought back. I just did this and didn't remove the TB from the car. Used ISO Alcohol and lots of q-tips and rags. Down the road I might pull the intake manifold off for a deeper cleaning this spring when it is warmer....and will replace the fuel injectors as they are starting to run a big rough as well. Spark plugs are newish. Job took 90 min..but I had don't it before and was very slow and methodical. But needed on white 08 with 128K miles.