I am years old I am writing you about my...

Dear Car Talk

Dear Car Talk | Jan 01, 1996

Dear Tom and Ray:

I am 14 years old. I am writing you about my dad's car. He has a 1986 Dodge Aries with a four cylinder engine, fuel injection, and an automatic transmission. The car has 70,000 miles. Over the past year, the car has developed a problem that I think will become serious if a solution is not found. When the car is initially started in the morning, the engine revs uncomfortably high, probably between 4,000 and 5,000 rpm. It will not idle down unless it's put in gear. After that, the car works just fine. My dad has taken the car to two different mechanics on several occasions. They checked the fuel injection system and replaced the oxygen sensor, but it did not help. I am worried that if this problem is not cured, the engine might blow. Please help!

RAY: You're absolutely right, Edward. The worst thing you can do to an engine is rev the heck out of it the moment it starts. And I agree with you, the engine might blow.

TOM: And you'd better hope it does, Eddie boy. Because if this heap ends up being your car when you get a license in two years, you'll never get a date!

RAY: The oxygen sensor was a bad guess. That wouldn't cause racing on startup. I suspect that the engine is running fast all the time, and it's just much more noticable when the idle is further boosted on cold starts.

TOM: So the first things I'd check would be the fuel pressure regulator and the central fuel injector. But even a coolant temperature sensor or MAP sensor that's gone haywire could cause excessively high idle.

RAY: The good news is you're in a good position to find this problem, because it's predictable. It always happens first thing in the morning when you start the car. So you can always leave the car with your mechanic overnight. And when he starts it up and it races for him, he should be able to diagnose it.

TOM: But I'd strongly consider keeping mum about this, Edward, and letting "automotive Darwinism" take its course. Just tear this column out of the paper before Dad sees it. And if he asks what happened to his Tom and Ray column today, just tell him you had an urgent need to spit out a big wad of chewing gum.

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