98 V70 Heavy Mis-Fire

Post by **rmmagow** » 20 May 2014, 06:08

This morning I had to accelerate hard with a cold engine.
Multiple mis-fires, P0300, 301, 302 etc, flashing light. It calmed down, I reset the light and continued driving. After wall warmed up, I hit the gas hard on the highway, no mis-fire but a pending 304 came up. Cleared that and NO CODES after a 50 mile run at some high speed and some pedal to the metal blasts.

My Question. 55K miles on new Volvo plugs, new Bougicord wires and new Bosch cap and rotor. I use mid-grade gas in it. The major difference is I used a new gas staion, i.e. it is new too, just opened and very very high volume station. This was the first time I filled up there.
Other than this, idle is so smooth one would think it stalled, 25.5 MPG and only a P0455 needing attention.
Is it time for plugs already? Thanks

Post by **precopster** » 20 May 2014, 08:02

55 k miles is a ton of mileage if they're just copper cores. I never got standard plugs to last more than 35 k miles or about 50,000 kms.

You could try resetting their gaps if they're too large but at this mileage I would just throw them out.

Post by **rmmagow** » 20 May 2014, 14:17

Volvo plugs are considered copper core right? I'll toss them then. 50K isn't too disturbing anyway for such an easy job.

Post by **MoVolvos** » 20 May 2014, 18:00

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https://www.matthewsvolvosite.com/forums ... =1&t=61696

Not sure if you read this thread on plugs but my Iridiums have been great thus far. Also check to make sure there is no or not too much ethanol in the fuel at the new gas station. (Sorry, you read it but I needed to re-read it).

Blessings,

BKM
_

Post by **erikv11** » 21 May 2014, 07:21

Volvo OEM plugs are three-electrode platinum (not copper) and can't be gapped, FWIW.

Agreed, I'd replace them at 55k and feel good about the decision even if it doesn't fix the misfires. But it might!

Post by **jblackburn** » 21 May 2014, 08:41

erikv11 wrote:Volvo OEM plugs are three-electrode platinum (not copper) and can't be gapped, FWIW.

Agreed, I'd replace them at 55k and feel good about the decision even if it doesn't fix the misfires. But it might!

The turbo ones are just single prong.

All plugs use a copper core, but the tip/ground strap material is what differs.

Post by **erikv11** » 21 May 2014, 09:18

Sure on the single electrode, but nowhere in the post title or post does it say turbo ...

Good point about the copper cores, I wasn't paying attention.

Post by **jblackburn** » 21 May 2014, 09:20

erikv11 wrote:Sure on the single electrode, but nowhere in the post title or post does it say turbo ...

Good point about the copper cores, I wasn't paying attention.

Familiar with the poster's car - it's a 1998 V70 AWD

Post by **rmmagow** » 21 May 2014, 09:30

Picking up a set of Volvos at Tasca tonight. Didn't get any mis-fire today though, and I tried. All things considered, the old car had itself a great winter. Started every day no matter how cold, low to mid 20mpg all season and I drove it pretty hard. New plugs, third and fourth tranny drain, Radiator flush-n-fill w/new thermo and ECT planned. Hell, I might even run over it with a clay bar and some new polish. Starting to feel as friendly as an old dog.