Remember. Never touch new halogen bulbs with bare fingers.

Hi all, first time posting.

i30 Wagon, GD, 1.6ltr auto.

Starts fine, accelerates fine until it hits 3000rpm and cuts fuel (not fully), then acceleration is sluggish.

Initially thought it was missing so replaced plugs and ignition coils.

Does this in auto, or sitting in neutral or or manual shift of auto (tried to see if it was anything to do with box)

Thoughts? Is this limp mode? No engine light, buying a fault code reader tomorrow.

Assuming something is telling the ECU to cut fuel?

That's for a complete switch, the rubber boot is integral to it. Just prise the old one out, unplug the connector, plug it into the new switch and snap it into position. The OEM part number is 81260-A5000, and is for the GD hatchback. I could have paid £40+ for a genuine Hyundai/Kia part, but they're not exactly proving to be very durable. I'm surprised at the number of second-hand ones being offered on eBay where the rubber boot is falling apart.

I just replaced the switch on my car, and also on a similar car we just bought for my partner. About £11 for a 3rd party equivalent. It's quite easy to prise out the old switch at one side, then snip or break off the retaining tab. Push it back in, then lever it out on the other side, it's then easier to pull out the other side where the tab has been removed.

This may help