98 S70 GLT Misfiring Under Load Topic is solved

Post by **wizechatmgr** » 20 Feb 2020, 15:48

The only ones I know of that are "actually" pre-gapped from the factory and could somewhat be relied upon are the Bosch +4 plugs.

Plugs get the hell beat out of them in manufacturing and shipping.

I had NGK iridiums from my motorcycle that were perfect ~14k miles later. That said, with such minor mileage, of course they were perfect!

ferocity02 · Post by **ferocity02** » 20 Oct 2020, 11:36

Well... the misfire has returned approximately 5 months and 1500 miles after I thought I fixed it back in February. Once again, it misfires under load and seems to be worse when the engine is very warm and while climbing hills.

I gave in and purchased the OEM Volvo plugs for the turbo. Seems like a 50/50 split between people using OEM vs. basic copper plugs. I'll drop these in and report back.

luckykolo · Post by **luckykolo** » 26 Oct 2020, 21:02

Anyone has any experience with resetting misfiring codes? How quickly they are coming back if the problem persists? I just want to eliminate the "ghost" code scenario before diving into serious troubleshooting etc. My car is Volvo 98 s70 Base 150 000 miles and has the history of some codes popping up and disappearing. My code was P0302. I inspected spark plugs for torque - (I replaced them about 6 months ago). Spark Plugs Wire Set is old - 16 years old as a matter in fact. No corrosion. Applied some dielectric grease and put some fuel treatment into the tank. I drove so far about 50 miles. No code. Having said that, monitors on the car are not reset fully. It takes log time on this car. Nevertheless I would think, that misfire would pop up immediately, am I right? Thanks

Post by **abscate** » 27 Oct 2020, 00:06

No, misfires have to occur for a certain amount of time under certain conditions; it is not a single event trigger. Most error codes work this way.

Cookeh · Post by **Cookeh** » 27 Oct 2020, 02:47

Coppers are notorious for increasing their gap with usage. Did you by any chance check the gap of them as you removed them? You may have simply needed to re-gap them.

Don't fall for the nonsensical idea that only Volvo plugs will run right on the car - its absolute tosh.