Traverse City Record-Eagle

Archive: Sunday

February 10, 2013

Don't ask us; ask the computer

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Dear Tom and Ray:

I have a '93 Toyota pickup with a six-cylinder engine. I live at 6,000 feet, and when I'm there, my truck runs fine. But when I go down to sea level, the truck is very hard to start. It cranks but has a hard time turning over, then when it does finally turn, it runs roughly until I get the truck on the road and the RPMs are up. Then it runs fine. The elevation is the only variable. Any ideas?

-- Celina

TOM: Well, first you have to tell us how long the "Check Engine" light has been on, Celina. Then we'll decide how many yards to penalize you for "withholding information."

RAY: Problems like this rarely occur without the computer setting a Check Engine code. So if your light IS on, you need to have the vehicle scanned for trouble codes. That'll usually help pinpoint the source of the problem.

TOM: If the Check Engine light isn't on yet, perhaps because you spend limited time at sea level, where the problem occurs, then you may have what's called a "pending code." That means the computer has detected a problem but it hasn't happened with enough regularity to set the Check Engine light yet.

RAY: But a scan still will tell you if there's a pending code stored. So next time you're at sea level, while you're experiencing this problem, take the truck to someone and have it scanned.

Dear Tom and Ray:

For the past four to six weeks, when I start my Chevy Trailblazer (2004) first thing in the morning, the smell of gas and sometimes oil comes out of the air-conditioning vents. Once the car has run for five minutes or so, the smell dissipates and does not come back for the rest of the day. We typically keep the car in the garage overnight.

My husband does not think this is a big deal, since I have taken it to the mechanic twice and they didn't find a problem. Is my husband right that I should not worry?

-- Shannon

RAY: I'd be concerned but not alarmed, Shannon. Let's assume that what you're smelling is gas, rather than oil. What do you need to be concerned about when you smell gas?

TOM: Fire usually is at the top of my list. And to the great thrill of every hungry liability lawyer in the country, I'm going to suggest that the risk of a gasoline fire due to your particular problem, Shannon, is relatively low (not nonexistent, but low). Why? Because it's been examined carefully by mechanics twice, and they've found no leak.

RAY: It takes very little gasoline to make a lot of gasoline smell. And if your gasoline smell is dissipating after five minutes and not coming back for the rest of the day, it's probably being caused by a very small amount of seepage.

TOM: That said, breathing gasoline fumes is not good for the old brain cells. So, for that reason, I would ignore your husband, and push to get this fixed.

RAY: When you park the car at night, the fuel system is still under tremendous pressure. My guess is that as the engine cools down, some small fitting or hose shrinks a little and allows a little bit of gasoline to seep out.

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