1998 Volvo S70 Misfiring--Tried Many Things

googs185 · Post by **googs185** » 13 Aug 2010, 18:51

Hey guys,

I've been trying to diagnose the problem for a couple of weeks now. I have a pretty bad loss of power when driving my '98 S70 base model. Putting it in 4th gear or even 3rd up a hill going 50 mph I still lose speed when I floor it. I got the codes out and I changed the O2 sensor, the distributor cap and rotor, and the fuel filter. I've also changed the spark plugs and used the spray water test to check for faulty spark plug wires to see if there was any arching. I'm still getting the D03xx codes for misfiring in a few cylinders and also the code for random misfires. What could be causing the issue? I've yet to check for vacuum leaks, but I am going to. Could it be the ignition coil? Would it cause such severe misfires? Another thing I was thinking about was the timing. Could the timing belt be off and cause all the misfires? I'm stumped!

Anthony

pablotar · Post by **pablotar** » 13 Aug 2010, 20:45

. I know that a shop that was trying to diagnose my car did that water check thing. A week later it was still running rough. I pulled off the spark plug boots and found water in there. It stopped misfiring after I dried it off.

Post by **marginal** » 13 Aug 2010, 21:17

Why don't you change the spark plug wires and put dielectric grease on their ends while installing them?

googs185 · Post by **googs185** » 13 Aug 2010, 21:19

Even if they aren't arching when I take the valve cover off? They could still be bad?

Post by **marginal** » 13 Aug 2010, 21:24

Of course they could.
I bought some Bosch from Amazon, life time warrantied ...

Post by **marginal** » 13 Aug 2010, 21:26

Here: https://www.amazon.com/gp/product/B000BY ... ss_product

Post by **marginal** » 13 Aug 2010, 21:28

Have you tried looking at the wire's ends as pablotar suggested?
I remember I had firing problems, and when I unplugged the ends there was corrosion on them.

Post by **Ozark Lee** » 14 Aug 2010, 05:31

I bought some Bosch from Amazon, life time warrantied ...

I bought the same wires and had nothing but trouble. Once I put the Bougicord wires on I have had no problems since.

Bosch is great for the cap and rotor and I have had good luck with the cheap Bosch copper core plugs but my '94 hated the Bosch wires.

My 2c,

...Lee

mikennedy12 · Post by **mikennedy12** » 14 Aug 2010, 09:58

Try the mass airflow sensor. I had a similar problem. Changed the plugs, wires, and O2 sensor . Mass airflow sensor fixed it!

googs185 · Post by **googs185** » 14 Aug 2010, 10:05

Thanks guys I'm gonna try checking the ends of the wires and the mass airflow sensor. How much is the sensor? It can really cause all the cylinders to misfire like that? How much would one run me?