Just had mechanic change spark plugs @141k miles, 2005 rx330. Gas mileage is worse and acceleration is worse. Four days after picking it up, the engine totally stalled as I was idling at a stop light. It cranked back up immediately and it hasn't happened again, but before I call my mechanic, I wanted to see if there was any input from you guys. What could the problem be?

 

You might want to scan for Diagnostic Trouble Codes.

 

Also what kind of plugs (brand) did the mechanic put in? I hope not Bosch. These engines do not like Bosch, or for that matter most any car.

 

the easy stuff to check for is the connections of the airbox to the throttle body..otherwise, there are a few other possibilities that may be causing your poor performance depending on the method your mechanic used to get to the plugs. Any vac leaks from poor sealing of the intake manifold, missed vac hose connections, improper torque spec of the spark plugs as well.

 

Check Engine Light on? Maybe not since OP did not state so. What kind (Spark plug brand) did they use?

 

Thanks for the replies so far. @thomas1, not sure. @fastnoypi, good suggestions, I can have him check those things. @mandyfig, check engine light is not on.

 

Could it be possible that I just got a bad tank of gas?

 

fastnoypi, pinoy ka ba?

 

yup but my tagalog sucks