Hey guys. im new on here but not really new to volvos. Im a member on turbobricks. Anyway i cant figure out whats up it. i just got a 94 850 turbo sedan today with 51000 mi!! yea. The 1st owner was a navy pilot who bought it new and never drove it. in fact according to the previous owner it sat for ten years! any way the previous owner had it for about 6 months. anyway the car has a misfire on cylinder 5. but sometimes it does it sometimes it doesnt. drove it for 15 min earlier with nothing. no check engine. nothing. then i go to start it and its missing and check enginr light comes on. pull the code its misfire on #5! wtf?! So i compression test it and when its not acting up i have about 160 all across the board! when its being retarded its like 85! PLEASE HELP ME!! Is it a sticking valve? Cam follower? idk...

 

Stage One needed first. Get some good new parts on her first. Sounds like a bad plug or wire.
You have compression, I would rule out a valve.

 

Im planning on it. But if it has low compression when its acting up wouldnt that have something to do with my valvetrain? or if the injector is sticking open and soaking down the cylinder would that give it low compression? It also smells very heavy of gas inside the car once in awhile

 

If it was a valve you wouldn't have good compression at all. I agree with previous poster, sounds electrical (plug or wire).

 

I'm gonna join the bandwagon here and also vote plug or wire. if you smell fuel, it could be because what's going into #5 isnt getting burned due to a misfire.

if you pull the pug, you should be in a MUCH better position to determine what's going on based off how the plug looks.

With a car that has been sitting that long, doing a stage zero would be high on my list. Replace the plugs, plug wires, cap, rotor, coolant, thermostat, oil, trans fluid, and at least clean the O2 sensors. That should get you in a good place.

And even though mileage is low on this car, I'd probably go ahead and do a timing belt, serpentine belt, and water pump as well. After all, 10 years of sitting is generally not kind to rubber parts.

 

i already did plugs wires cap rotor etc. the plugs all look fine. the #5 plug had a yellow film on the tip. Whats that mean? i also noticed when i pulled the ic hoses off, around the throttle body area is standing fuel.??? What the hell?

 

So you're saying you've actually checked the compression when it's acting up and #5 is below 100 psi??

Plus the car sat a lot?

Uh, no brainer; sticking valve(s). Run several tankfuls a gas through with a injector cleaner additive and maybe some Marvel Mystery oil (good top end lube) in gas and oil.

 

i also pulled the code 5-5-5. whats that? It was something like #5 misfire TWC damage. WTH?