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2003 Highlander Start & Die

My HIghlander with only 72K miles has an intermittent problem. I start it and it immediately dies. To get it going, as soon as engines starts I push and hold accelerator at about 1500 rpm for about 3 minutes, then ease off accelerator and generally no problem for the rest of the day. Been to regular mechanic with it twice, but car doesn’t do it then. May go several weeks without this happening, then will have a series of these episodes. Not battery. Not throttle body. MEchanic doesn’t think it’s the type of gas being used. ANy ideas?

Well my first guess would be a faulty Idle Air Control Valve. But you don’t want to guess on a $350 part. I assume you have no Check Engine light on, and your mechanic didn’t find any fault codes to start him in the right direction.

Your mechanic should be able to figure this out if the problem happens while he has the car. But that means you may have to leave it with him for some time.

You can at least ask to have the IAC valve checked and cleaned, including careful scrutiny of the IACV wiring.

I’m assuming this is not the hybrid Highlander. There is a “system” to enrich the fuel mixture for cold starts. When the car warms up the computer (feed by info from sensors) reverts back to the standard mixture until the car is “cold” started again. Since you are bypassing the cold start system by keeping the rev’s at 1,500 for a few minutes I’d look at the IAC valve as others have suggested. If it checks out then you are not getting a sensor to tell the computer the motor is cold. So, the sensors for coolant temperature are suspect.