1998 5 Cyl Multiple Misfire Cause Survey

[superfeed]

Good People,

I am trying to solve the sudden multiple misfire flashing CEL and running like crap problem on my V70XC. My next step will be to check compression. The problem happened when accelerating aggressively and has remained. Smoke was rising from near exhaust after shutdown. 800 miles previous to the problem I had changed plugs with NGK copper and wires with Bougicord. It was running pretty good with no codes before the failure. Afterwards, had misfire codes for individual cylinders and multiple random misfires.

I have spent probably 25 hours reviewing discussions from previous similar problems on this site and others. I would say the solution is probably included in the discussion 15% of the time. I also noted that while many times it was suggested to replace the crank and/or cam sensors, I do not remember seeing where it actually worked for anyone.

This is what I have done:
Checked timing of crank and cams
Replaced cap and rotor
Replaced coil
Replaced cam position sensor
Replaced crank sensor
Made sure sensor wires are routed far from coil wire.
Pulled the plugs - Strange, plugs 2, 3, & 4 were wet as if not firing. I started the car and the pulled the plug wires to each cylinder. I think it is only running on 1 & 5. It certainly feels that way!

Just curious as to what has worked for any of you that have experienced this problem. If you could just leave your solution, I'll tally the results.

Thanks,
John Gregory
Portage, MI

[shaker_chi]

I had the same issue with a 98 S70 T5. I did have a misfire until I accelerated, just idling and normal driving it was fine. My problem turned out to be a bad spark plug wire. If I were you I would put in O/E spark plugs. I have 2 S70's and 1 850 and I have to say that these cars are very picky about their spark plugs. I've used the copper in my N/A 850, but they did not perform well in either of my T5's. I know Bougicord is O/E, but I went with the IPD set on all my cars. I see you have done a ton of work, only thing I can think of is makes sure the plug wires are attached properly at both ends.

[AVIP]

The problem on my s70 was the octane gas in my town. Low grade is 86 causing the car to miss. I had to use premium to clean it up

[erikv11]

I had multiple misfires due to a blown rear cam seal, intake cam. but you would have seen the oil and/or moisture in the cap when you pulled it for replacement.

[abscate]

Multiple misfires on my turbo car caused by loose induction tubing, top intercooler pipe. Running was so poor you would think you had trashed the engine.