plug wires. you should get a haynes or chiltons volvo 850 manual. lots of good pics and descrptions in those...

using some seafoam will do you a world of good

i guess you already got some new plugs, but...

after i bought my 850 wagon i did a big tune-up and i took out my old volvo OEM plugs with roughly 70k miles on them. they were worn normally, but pretty well worn out. i replaced them with bosch platinums +2's for a month or so. (the nice man at the franchise auto parts store had a sale that week) i didn't really notice a difference in performance. so, i took the bosch platinums out and put in the Volvo OEM triode plugs and was much happier. the engine seemed more resonsive and smooth thru the 2k~4.5k RPM range and my mileage improved about 1MPG. been running with the Volvo OEM plugs for more than 10k miles and they are smoothy-smooth.

i recommend the OEM plugs, they dont need gapping (factory set) and its what those silly engineers and scientists wanted us to use in the first place. i think they cost $10 less than the bosch on sale too, even after i paid shipping from FCPGroton.com!

oh, and i'll sell ya the the bosch +2's for cheap! only about 100~150 miles on them. still shiny, like new! still have the box!

 

woods...thanks but i just installed the oem volvo plugs that you mentioned just yesterday..they do seem a bit better than the ones that where in there...i had used some seafoam that goes in the tank to clean out the system..didn't notice much of a difference...i was thinking that maybe the gas filter is old and blocked and not sending enough gas??? or maybe the o2..but it would have given me a code...right?\
thanks
fabs

 

TECH...if you want, send me a PM with your info, i'll to get in touch with you when we arrive..take it easy..
fabs

 

O2 yes would give a code. Check really good for Vaccum leaks. Try to find a scanner or something to monitor the O2 sensor. Or it could also be a bad Mass Flow sensor.

P.S. I will send a PM.

 

Tech..hey i got your message,sent you one too.....
i will look for leaks, i was thinking maybe a clogged fuel filter..i looked at it today and it does look kinda old, can't see the writting on it. if it where the maff though wouldn't it really make the car idle/run like crap? i know, i've seen a car with a bad maff..
fabs

 

Sometimes they will run bad other times they won't.

 

I'm going to resurrect this one.
We decided to do a tune up due to rough idle and here is how it went. We replaced the plugs and wires but the parts store had to order the cap and rotor. The car ran a little better with just the plug wires and plugs. The key word in that last sentence is ran cause after we received the new cap and rotor and installed them, the car will not start. I thought my son might have messed up the firing order so we bought a repair maual. The manual shows the order but it is hard to determine where the #1 spot is on the cap. We did try moveing the wires one position each way but still nothing. I would try putting the old rotor back in but it was so fried that it fell apart. What are we missing?

Thanks

 

If the old cap was original it is numbered.
Sounds like one of the new parts are bad.