2007 Sienna Cylinder Misfires
Asked by SPH1951 Feb 24, 2017 at 12:47 PM about the 2007 Toyota Sienna XLE
Question type: Maintenance & Repair
I have experienced repeated cylinder misfires. It happen after driving at highway speeds after about an hour or two. I pull over and shut the engine off for about 5 minutes start it up and it runs smooth. Once back on the road it will do it again (raqndomly) and I have to pull over again. Have recently (2 months ago) replaced all spark plugs and injector coils...still getting random cylinder misfires but only when traveling at highway speeds. Latest codes were for cylinders 2 & 4.
2007 Toyota Sienna 231,000 miles.
6 Answers
Check the compression on those two cylinders, they are side by side. If it is low then there is a problem in though's cylinders. Could be something like a rocker out of adjustment or a head gasket.
How did you fix it? I have the exact problem on Toyota Sienna 2007.
It went away after treating the gas with a product called Sea Foam Motor Treatment. I got it at NAPA auto parts. the tech called it a "tune up in a can". It appears as though the increased level (%) of ethanol in the gas. I now check the % posted at the gas pumps to insure that it is posted as no more than 10% ethanol. After 2 treatments in full tanks of gas the problem resolved.
I had the same problem and changed the Cadillac(sp?) converter this cooled everything down and now it works great.
update - it didn't fix it, I also replaced the coil packs, spark plugs and fuel pump and it is still doing it.
