We have a 2004 Toyota Prius. It has 145k on it and I'm having the following issues. 1. Loss of acceleration; it runs a little rough when it runs good, but I notice there are times it takes a lot of acceleration to get it up to 25-30mph. 2. "Trip Info" goes completely blank when I come to a stop; when I say blank, it means it shows the engine is doing nothing and the battery is doing nothing. I'm sure we're due for new spark plugs and I plan on doing that this upcoming week, but I'm wondering if it could be a more serious issue, like the engine or transaxle. Here is what we've had done on the car so far recently. 1. Flushed the transmission fluid 2. The usual oil change every 3k. 3. Replace the main battery (it went dead around 139k and it was under warranty here in California) I'm hoping it just needs new spark plugs and I'm not looking at a four-figure repair.
I hope that you will only use the correct NGK or Denso iridium spark plugs. Do not use some cheap alternative. Also, I suggest you check the engine air filter (the dirty side is on the bottom) and replace if you cannot see light through the filter when held up to sunlight.
By the way, 3k is really much more often than needed for oil changes. It's just a waste of money. 5k miles is plenty. Based on used oil analysis even 7.5k appears safe.
