It started as a subtle shudder at highway speeds, barely noticeable in the 2014 Buick LaCrosse that rolled into the shop. By the time the owner pulled into the bay, the check engine light was flashing — a sure sign of a misfire severe enough to dump raw fuel into the catalytic converter. The scanner pulled a P0302 code: cylinder two, dead. The owner was convinced it was a fuel injector issue, a common assumption. But the data told a different story.
The short-term fuel trim on cylinder two was negative, indicating the computer was pulling fuel because combustion wasn’t happening. That points away from fuel delivery and directly at spark. A quick swap test — moving the suspect coil to another cylinder and watching the code follow — confirmed what the evidence suggested. The factory coil, with 87,000 miles on it, had simply given up. This is a story we see weekly, and it’s why the aftermarket for Buick ignition coils has become so critical. When OEM coil prices push past $150 per unit, shop owners and DIYers alike are looking for a reliable alternative that doesn’t compromise on spark energy.
Key Specs: OSRAM OS2003 Ignition Coil
- Part Number: OS2003
- OE Reference: 10497771, 19353734
- Type: Direct-ignition coil (pencil-style)
- Compatibility: Buick models with the 2.4L Ecotec and 3.6L V6 (check fitment)
- Construction: Epoxy-sealed housing, brass terminals, high-grade copper windings
The repair itself took less than an hour. After removing the engine cover and the coil bolt, the old unit slid out with minimal fuss. The new OS2003 | OSRAM Ignition Coil | Fits Buick | OE# 10497771, 19353734 — branded under OSRAM, a name more commonly associated with lighting but with a solid footprint in automotive electronics — seated perfectly. The connector clicked with the same positive engagement as the factory part. We replaced the spark plug at the same time, an easy upsell that prevents a comeback in 10,000 miles.
Here’s where the real-world performance matters. After clearing the code and resetting the fuel trims, the LaCrosse idled smoother than it had in months. A road test confirmed the fix: the shudder at 65 mph was gone, and the throttle response felt crisper. The owner reported a 2-3 MPG improvement on the next highway trip, a direct result of restored combustion efficiency. The OS2003 runs within the same heat range as the OE unit, so there’s no risk of pre-ignition, and the internal circuitry handles the 40,000-volt demand without the erratic firing that plagued the failing unit.
Pro Tip: Don’t just replace the single failed coil on a high-mileage Buick. If one pencil coil has died, the others are statistically close behind. While the OS2003 is affordable enough to replace all four or six at once, if budget is a concern, at minimum replace the coil on the cylinder with the highest recorded misfire count in live data.
Six weeks later, the customer returned for an oil change. No codes, no complaints, and the fuel trims were still sitting near zero across all cylinders. The OS2003 | OSRAM Ignition Coil | Fits Buick | OE# 10497771, 19353734 held up through a brutal summer heat wave, proving that the aftermarket doesn’t always mean “lesser.” For a shop owner, stocking the OS2003 makes sense — it covers a wide swath of GM platforms, reduces warranty callbacks, and at roughly half the cost of the dealer part, it’s a profitable upsell that the customer actually appreciates. If you’re staring down a P0300 series code on a Buick with over 60,000 miles, skip the fuel system diagnosis until you’ve verified spark. Nine times out of ten, it’s the coil.
Recommended Part: OS2003 – OE-grade replacement, in stock now.
