[twyrick]

I recently purchased a used 2013 Smart Cabriolet from a local Toyota dealership's lot. (Price seemed pretty good for what was essentially a fully loaded Smart with 57,000 miles on it. And I needed something inexpensive but suitable for our kid to drive to and from work and school, once she gets her license. Good, cheap transportation around town for me in the meantime.)

After I started driving it a little bit more than what I could experience during the initial test drive, I realized it just wasn't running very well. It'd suddenly lose power and then "surge", idled rough, etc. Looked to me like the spark plugs were never changed before on it (bolts holding down the coil packs were rusted in place!) and the air filter was really dirty. (Also changed a dirty cabin air filter while I was at it.) After doing all of that, it runs MUCH better. But I've still noticed that when I'm in stop and go rush hour traffic on the Interstate, it stumbles occasionally if I try to creep forward at 5MPH or so. It hasn't actually died on me but a few times, it sounded like it was going to, until I gave it more gas.

I'm not much of a mechanic, although I know the basics. I checked for things like rips/tears in any visible hoses, but didn't see anything. (The rubber hose I had to disconnect to get room to access the far right-hand spark plug was still "rubbery" -- not brittle from heat like you sometimes encounter.)

Could this be an issue that will go away if I get that "valve lash adjustment" done that Smart recommends at 60K miles as a service item?

 

[jimvw57]

Congratulations on your car, you have a unique machine and unfortunately they do have some character to them. The air filter will cause some roughness and at 57K miles should have been replaced.Plugs are something I leave until they don't want to work, or I see a drop in the MPG department.
The stumbles at rush hour traffic is because it is a manual computer controlled transmission and it is programmed to shift as early as possible into a higher gear. Stop and go traffic can be a nightmare! when you are in that situation,allow more of a following distance from the car in front of you and consider dropping into manual mode and handle the shifts yourself.

They probably didn't mention that it is a manual transmission complete with a clutch run by the computer. They usually don't see a clutch pedal so it is assumed to be an automatic. (it's not) The valve lash adjustment won't make it shift any better, but is a good idea as we have seen quite a few cars dropping valves, etc.