Spotting and Troubleshooting Engine Misfires in Real Kiwi Driving
Dealing with an engine misfire can give you a real headache — especially if you’re just trying to get across Te Rapa Rd or crawling along Boundary Rd in Hamilton’s rush hour. When your car’s not running right, things can get sketchy pretty quick. Whether you’re driving a Mazda Axela from Morrinsville or a Hyundai Tucson in traffic out by Rototuna, here’s how we usually check for car engine misfires in the workshop, and how you can spot them before they wreck your week — or your wallet.
1. Start with the Spark Plugs and Ignition Coils
First thing we do is check your spark plugs and ignition coils. Seen plenty of Toyota Avensis, Suzuki Swifts and even the odd Peugeot 308 come in running rough just from tired plugs alone. All the stop-start through Cambridge Rd and the harsh winters we get can make them fail quicker.
If you pop the bonnet, have a look for cracked plugs or heavy muck from years of 91 octane fuel. Don’t forget those coils — a dodgy one means you might as well be running on three cylinders. Pull them out, check for wear, and if in doubt, replace. Got a hold of a multimeter? You can test the coils. Makes a massive difference to performance and fuel use. For more on it, check our spark plug testing service.
2. Fuel System Checks — Injectors, Pumps & Filters
Fuel delivery’s a big deal, especially if you do a tonne of start-stop along Cobham Drive or head out to Kihikihi every week. Seen Honda Insights and SsangYong Rextons lose power and cough because a filter’s clogged or injectors are sticky from cheap fuel.
Start by checking your fuel injectors for gunk or leaks. Sometimes a clean fixes it, other times they need a swap. Pump acting up? Munted fuel pressure will cause misfires, especially if you notice it struggling up the hill to Dinsdale. And don’t ignore that fuel filter — swap it if it’s overdue. Our fuel filter replacement service covers it if you’re not keen on tackling it yourself.
3. Vacuum Leaks — Check Those Hoses!
Vacuum hoses gone brittle is something we see all the time — you get that more with the old European cars, like Citroën C4s or Alfa Romeo Giuliettas, but even regular Nissans from Te Awamutu or Raglan can get this. You notice rough idling, surging, sometimes a hissing under the bonnet.
Take a good look for cracks or hoses that have slipped off after bumping over Hamilton’s infamous potholes. Can’t see anything obvious? Get a smoke test done. Any leaks, get them fixed or swap out the hoses. Restoring a tight seal sorts out plenty of misfires. Read more about it in our vacuum leak repairs guide.
4. See What the Car’s ECU is Saying
Modern cars — even regular Mitsi Colts or Kia Souls — have an Engine Control Unit (ECU) that’s smart enough to spot misfires. One of our techs will use an OBD-II scanner on nearly every job, and it’s gold for finding exactly which cylinder’s out or if a sensor’s thrown a wobbly.
Plug it in, check the codes and see if it points to a sensor or even a random wire issue. We see a fair few weird ones with imports from Japan or Europe. Clear the codes after fixing — your car’ll thank you. If you want to dig deeper, check out our ECU replacement service.
Give Your Car a Fighting Chance
So if your engine’s running rough, hesitating, or chucking a warning light as you drive over to Chartwell, don’t just ignore it or hope it’ll sweeten up. Catching misfires early saves you bigger repairs and keeps you safe on the roads — whether it’s Hamilton city traffic or country roads around Tamahere.
If you want a proper check-over, or you’re not keen on having a crack yourself, swing by Grimmer Motors. We’ve seen pretty much everything under the sun — hybrids, classics, all sorts — and we’ll treat your car right.