1998 S70 10 valve M56 tuneup, stutter at mid rev

[precopster]

Rotor button, cap and plugs should be thrown and replaced. The non turbos should take the triple electrode plugs as pictured. I've used turbo plugs (single electrode) in non turbos and the electrodes seem to have an accelerated wear rate and need replacing more often

Other manufacturers such as NGK also have equivalents to those plugs pictured such as BKR6ETUC

[Ocelot]

Hey guys! Small update. I've ordered new OEM sparkplugs and a new fuelfilter to begin with, since they are overdue. I've observed some details concerning the hiccups.

The engine hiccups after long drives, only on a warm engine.
The hiccups only occur between 1000 and 1500 rpm.

Since there are no warning lights lighting up on the dash, I have this theory that it might be fuelrelated. Maybe a dirty MAF, or a dying... how do you call this in English... we Dutchies call it a "nokkenassensor". It's the sensor that monitors the camshafts rpm...

[abscate]

In Engels, "Camshaft sensor" of "cam sensor "

[bmdubya1198]

Could be a cam sensor or crank sensor. I had that issue with my GLT where I'd begin to pull out of an intersection and the car would jerk and nearly stall before picking back up. Turned out it was the crank sensor.

Either of those sensors could cause a similar issue, and won't always throw a code.

[jeffsws]

I had similar issues and new spark plugs and fuel filter solved it for about a year. It then got really bad to the point I could barely drive the car at times - and only when warm. Replacing the wires, cap and rotor fix it up perfectly. So if any of those parts are not done, I would change them all at the same time.

[Ocelot]

So I think I fixed the hiccup, in replacing a part I did not view as the culprit at all. I checked the battery with a scantool and it said "recharge and check again". So I did. And then it said "replace battery". The current battery is an original Volvo battery and I checked the heat stamp on the foot of the battery and it's FIFTEEN years old haha. Talking about quality! I've ordered a new one, I'll keep you guys updated!

[abscate]

Fifteen years? You can't get quality anymore.....

[Ocelot]

So I've been driving around with a new battery and so far no hiccups have occured. I have not made a long drive with the car so far, so I'm not sure yet this issue is resolved (because the hiccups would occur after a long drive). I'll keep you guys informed!

[Ocelot]

So today I finally changed the plugs, rotor and cap. The sparkplugwires are relatively new (5 months old) so I didn't change those. Most of the hiccups/stutter vanished with installing a new battery (I did that two weeks ago). After the tune-up I drove her around for about an hour and the entire drive was without stutter.

So I think that the issue is solved! Thank you guys for giving me advice on tackling this issue!