850R missing and backfire

**kyboy** · Friday 20th May 2016, 12:03

Hi there all,as above missing on HARD acceleration but fine if you build up speed gradually and this morning it's been back firing and popping more than usual is it over fuelling?? Plus boost leak?? Apart from this runs fine but is driven hard daily....ta!

**mitchyboy01** · Saturday 21st May 2016, 07:45

Sounds like it could be an ignition fault with the hesitation and back firing.

**martin_r_smith** · Saturday 21st May 2016, 08:52

What plugs have you got in there and how old are they?

**kyboy** · Sunday 22nd May 2016, 12:24

Originally Posted by martin_r_smith

What plugs have you got in there and how old are they?

That's my first call going to do cap arm and plugs as they haven't been done for a while!

**martin_r_smith** · Sunday 22nd May 2016, 12:41

Use volvo plugs.

**kyboy** · Monday 23rd May 2016, 22:06

Originally Posted by martin_r_smith

Use volvo plugs.

That's the plan just to be sure

**kmb** · Monday 23rd May 2016, 23:14

I just cured a very slight random mis-fire on my 850 T5 by replacing HT leads, rotor arm and dizzy cap (all OEM), the plugs had been changed 3k miles ago with Volvo originals...