2007 Hyundai Tucson Pricing and Specs

Most Hyundai engines with a rubber timing belt require belt changes every 100,000km. Stretching this interval is pushing your luck as a failed belt will destroy the rest of the engine. With that in mind, you’re already over that limit by about 10,000km, so a change sooner rather than later is in order.

The car will, indeed, drive perfectly even with an old timing belt. Until it doesn’t. At which point you have an engine bay full of junk and a big engine replacement bill coming your way.

That’s a pretty comprehensive rebuild of the fuel system, so it’s possible that something that was removed at the time has gone back on not quite the way it was. A shuddering as you slow down suggests that the idle speed is perhaps a touch low. You should be able to adjust the ide speed fairly simply, so the first thing to try is to creep it up, say, 100rpm and see if the shudder goes away.

A mechanic will be able to do this quickly and easily. If that’s not the problem, you need to go back and double check every fitting and fastener to make sure there’s no air or fuel leak that is causing the engine to develop the staggers. Were the new injector seals treated to a dollop of rubber grease before they were installed? If not, there’s a chance that fitting them may have put a small tear in the rubber seal which is now leaking.