Mechanics

I CHANGED SPARK PLUGS AND AIR FILTER TO MY . NOW CHECK ENGINE BLINKS 5 TIMES AND THEN THE VSC AND TRAC OFF COMES ON. WHAT IS WRONG?

2005 Toyota Highlander • 137,000 miles

After around three days from the time I changed plugs and air filter, my vehicle started to idle roughly, especially while the a/c is on. Feels like it wants to die but it doesn't. Is car safe to drive? What could be wrong?
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Johnortiz1
September 4, 2012.



The logical solution is the wrong spark plugs were installed since that is the recent history when the problem started. Some engines are very picky and can't use split-fire or other special plug designs. The gap must be correct too. If one of the coils wasn't seated properly the terminal on the end can burn away over time leading to a misfire.

Having the stored diagnostic fault codes read is a good place to start. The code(s) may indicate which cylinder is misfiring.

Caradiodoc
Sep 4, 2012.
Changed plugs(Needed Iridium plugs)and problem still exist. Is it air intake or oxygen sensor?

Tiny
Johnortiz1
Sep 4, 2012.
Having the stored diagnostic fault codes read is a good place to start.

The sensors you listed don't cause misfires. The Engine Computer adds extra fuel in cold temperatures so a high enough percentage vaporizes to burn properly. That's a product of the intake air temperature sensor. There's also a mass air flow sensor in the air intake. That tells the computer how much air, by weight, is going into the engine so the computer can command the correct corresponding amount of fuel. The oxygen sensors tell the computer how well the mixture burned. It's reporting on what already happened. It can't cause misfires either.

Caradiodoc
Sep 4, 2012.