Apparently I can't find pre-gapped spark plugs for this vehicle. I came across an online manual saying a gap of 0.028-0.032. But, it also seems that the Volvo manuals came with a lot of typos so I wanted to make sure. Search wasn't helpful. Should I aim for .28, .32 or just go for the middle?

 

So I just went for the middle, gapped mine to .030 and boy did they need them. I just bought this with 100K miles and I think the plugs were the original factory plugs. Very dark and with a gap of .040. I am really surprised it didn't fire off any codes or anything like that. I'm starting to like the toughness of these things.

 

https://www.fcpeuro.com/products/vol...0-xc90-8692071

When I bought my spark plugs, they indicated to me that they are pre-gapped.

 

I used pre-gapped Bosch FR7DP (4028) for years with great success on the turbo-equipped engines. Then they came out with their double platinum FR7DPP (6730) but I decided to leave well enough alone and stick with the tried-and-true plug. About the time that the WR7DPP+ came along, I started to have problems with FR7DP's center electrodes coming out of the insulator and closing the gaps. Perhaps their quality control on the older plugs had slipped. So I switched to the WR7DPP+ (also pre-gapped) and am having great success again.

Here is an ebay listing:
1 x Genuine Bosch Spark Plug +24 Super Plus FR7DPP+ Platimun Iridium | eBay

 

I just replaced my 07 XC70's sparkplugs not OEM, no pregaped three months ago, nor any car I had lately, I didn't even think about gaping them, car ran so sweet. the modern day engines sparkplugs do not need to gap.

 

Not true. If you have too wide of a gap, a turbo engine will misfire due to increased cylinder pressures.

I use pregapped plugs from Denso.