Reader Question: Fuel System Service?

Here’s the latest reader question, along with my reply!

Jetta Guy asks: My mother’s daily driver is a 2017 Toyota Sienna van. She also owns a small 2012 Toyota Tacoma automatic two-wheel drive that she uses for yard work and taking off the trash and taking the cats to the vet and such. Actually, I drive it more than she does but I’m happy to help out. About a year ago, I noticed that it didn’t accelerate like it should. It seemed to be dragging or holding back or something when I was going down the road. I’m not much of a gearhead, so I recommended that she take it to the Toyota dealer and have the transmission and engine checked out. They didn’t find anything wrong with it and didn’t do anything but maybe change the oil. I had also noticed that my mom’s van kind of drives like the truck. It has that feeling that something is holding it back. I thought it must be how Toyotas drive. Today she took her Sienna in for regularly scheduled maintenance. They recommended that she have the fuel induction system serviced and cleaned, so she agreed to let them do that. Wow! Drives like new. Smooth, no growl when accelerating, no weird holding back feeling in the transmission, instead, it’s perky and responsive. I told her that I think the truck needs a fuel induction service too and that that was what has been wrong with it all along. So what’s going on here and what’s the best way to make sure we maintain the engines in our cars for the long-term? Thanks for all your advice and insight about cars and everything else.

My reply: They basically cleaned the carburetor… if it had one! Instead, the cleaned the throttle body and maybe ran some cleaner through the injectors. It amounts to the same thing, which is to remove any accumulated crud. Fuel injectors have small orifices through which the fuel flows – analogous to a jet in a carb. If that little hole is partially occluded with varnish or such, the result will be less than optimal performance. A dirty throttle body will also cause similar problems.

The cleaning probably also took some gunk off the spark plugs, and now they’re firing properly, too.

As far as avoiding the need for all of this – or reducing the need: Not all gasoline is created equal. Some have better additives than others (e.g., Chevron which I try to use; Shell is also pretty good, in my experience). Avoid off-brand gas. It is cheaper for a reason.

Also – perform an Italian tune-up every now and then. Full-throttle runs will help clean off the varnish, too!

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