The plugs worked great initially. Torque and power was much better, and the gas mileage rose by another 2 mpg. I was really happy. Then, around 6 months later, the gas mileage started slowly dropping - from 46.6 to 44.3. Since that was the transition from winter to summer, I took it to be the normal Prius variation in mileage with temperature. Anybody who has a Prius notices this - you get much better mileage in summer than winter because the car warms up sooner and so the engine shuts off sooner.
On Wed., I was driving downtown when the engine suddenly began to chug. I thought it was an earthquake or something, Toyotas are usually reliable. Then the check engine light began flashing - whooo! whoo! red alert! That got me concerned. Fortunately, I was only a couple of blocks from my mechanic, so I slowly nursed the car to the garage and left it there for repair the next day.
The mechanic called me around noon the next day with the news. Apparently, the plugs had fouled and shorted out the ignition coil. He was really surprised, since the Prius comes with iridium plugs that supposedly last for 120,000 mi. I had the Pulstar™ plugs in for less than a year.
I asked him to give me the plugs, which he did, then today I called up Enerpulse and asked them to make good on their warranty, which is (quoting directly from their Web page):
We offer a 4-point guarantee on Pulstar™ Pulse Plugs. This means:
1) You can return the Pulstar™ pulse plugs for any reason within 30 days, no questions asked.
2) Pulstar™ pulse plugs will not harm your engine.
3) Pulstar™ pulse plugs will last 50,000 miles.
4) Pulstar™ pulse plugs will not void your warranty.
Near as I can tell, this incident violated at least 2) and possibly 3) if the plug that fouled shorted itself out too.
Enerpulse told me that I had to send the plugs and the ignition coil back to them, along with the bill from the mechanic and a letter explaining the situation. Fair enough. I guess they need to have the evidence before they are willing to cough up any money, since people do cheat.
I called the mechanic up again and asked if he had the coil. He did, so I picked it up today.
We will see whether they are as good as their word. Stay tuned.