new owner here(one week), my 97 854 t5 misses only when i'm giving it full throttle. i can give it anywhere for 10-90% throttle no problem, but as soon as i kickdown it misses. car is kind of inconsistent b/c i can kickdown and she takes off! i changed three vacuum lines from the turbocharger to the control valve beside the airbox, and one from the turbo to the intake manifold.

got a lot better but still misses under WOT. would spark plugs, plug wires, air filter, fuel filter or injectors be the problem. I may have to do a process of elimination to hopefully get a fix.

If anyone has an idea of the source of the problem, please chime in. It's a total blast driving this car!

 

I would do a FULL tune up and that should fix it.

 

long story short I got four oem volvo spark plugs and changed four of five. car runs excellent but after a while it misses slightly so it's a work in progress. at least i know there is no major issue only a full tune up is required.

Thanks for the response i'll keep everyone posted.

 

Your welcome.