I have a 94 volvo 850 t-5 110k miles, I having been having a constant misfire in cylinder #5, I changed the plugs, wires and fuel filter, now the code reader says random misfire. I'm now also unable to accelerate quickly from a stop. I can only gradually pick up speed, and the car will no longer go past 70 mph once I do get up to speed. Can anyone please give me an idea where I should look or replace next. I tried the search but could not find this issue in other threads. Just so I'm clear -- I'm having trouble accelerating, and a constant random misfire -- thanks in advance for any assistance

 

When you replaced those parts, did you replace them with OEM parts?

- Plugs: Genuine Volvo, Bosch or Champion
- Plug wires: Bougicord made in France
- Cap & Rotor: Bosch made in Germany or Spain
- Fuel filter: Bosch

Have you noticed any fault in the transmission (arrow on the dash, low/dirty fluid or lousy performance)?

Any blockage in the exhaust system?

See attached.


JPN

 

No I didn't use OEM parts, but still they were new parts - so even if they don't last as long, they still should perform like new when first installed. Yes/No?

 

No, surprisingly not. I installed non-OEM sparkplugs in my 850. I noticed right away that my engine would idle rough at stops and nearly stall. When driving on the highway, I would randomly lose engine power. I thought it was a bad air/fuel ratio but later found out it was a series of misfires by the new plugs.

Bought stock plugs from volvo and completely fixed my problem. Also, make sure when you buy new plugs (if you have to) that you buy the right ones. Turbo cars and non-turbos use different plugs....Turbos are more expensive

 

+10.


Jpn

 

I will put install OEM plugs tmrw to see if that helps, I will let you all know if it does. Hopefully it will. thanks for the input

 

I installed new OEM wires and champion platinum plugs - it's better but I'm still not able to go any faster than 50 mph - what gives. any ideas guys -- please help would a plugged cat cause this?

 

Champion Platinum are NOT OEM plugs.

 

Have you done a compression test?
Any more codes come up?
Last time you changed the fuel filter?

 

I have changed the fuel filter, the codes are a random misfire - I will take the car somewhere to have a compression test done. I'm running out of ideas and options.