Sticking throttle persists

Repairs unsuccessful; cable check suggested

DEAR CAR TALK: I have a 2001 Ford E250 van with a 5.4-liter motor. When you step on the gas and then let your foot off the pedal, the throttle drops very slowly. I’ve replaced the EGR, the throttle position sensor and the idle air-control valve, and I’ve cleaned the throttle body. I don’t know what’s wrong or how to fix it. Can you help? — Skip

You’ve tried most of the things I would have suggested, Skip.

Let’s assume you did all of that stuff correctly, and that you didn’t notice any scoring or wear and tear inside the throttle body that could cause the butterfly valve to get hung up. The next thing I’d look at would be a sticky throttle cable.

Check it by disconnecting the throttle cable from the throttle itself, and then operating the throttle by hand with the engine cover off. If the van returns to idle normally without the throttle cable connected, then you know it’s the cable.

If it’s not that, the next thing I would hope for is a good, old-fashioned engine fire. You’d be surprised how many mechanical problems an engine fire can solve, Skip. Good luck.

Dear Car Talk: I was wondering if there is a way for gas stations to add water to their tanks to make the gas stretch farther. I have heard differing points of view about this when I posted this question on a popular social-media Q&A. What do you say? — Julie

It’s possible. And it’s also impossible, Julie. More to the point, it’s possible for gasoline and water to mix temporarily.

If you shake up a container of water and gasoline, the water will be briefly suspended in the gasoline, but will quickly separate back out, with the water going to the bottom and the gasoline staying on top.

This trick is popular right now only with gas stations in Oklahoma, where they have about 5,000 earthquakes a month, thanks to fracking. That keeps those underground storage tanks shaken up nicely.

So the overall answer is no, it does not make sense for gas stations to do this, Julie. The water would sink to the bottom of their storage tanks, taking up space, and reducing the amount of gasoline they could store and sell.

And since the water would separate out, some customers would get only water, which would leave the gas station with a lot of ‘splainin’ to do. Got a question about cars for Ray Magliozzi? Email the Car Talk website at www.cartalk.com.