480 miss fire

[rambo_at_casvagas]

i hope some one can help me
i have recently just bought a 480 celibration and i am having some problems having looked at things that have been posted about missfires i am now at a loss the car has had new plugs, leads, cap, rotor, coil and flywheel sensor fitted by the pervious owner but still it miss fires when its been driven when parked up it tickes over fine and you can hold the throttel open and it dosent miss a beat but soon as you start to drive it it starts missing not all the time if you accseerate hard its fine just when you drive at a constant speed and that gose for any speed hope some one out there can help just thought i better tell you its a 2l injection 95 reg celibration

[B20F]

Did you check the diagnostic box's (http://http://www.am.torun.pl/~ja/volvo/diagnostic-system.shtml) fault codes stored @ socket 2? This can help you to find the cause.

Misfires are mostly caused by the flywheel sensor. You said the PO renewed it but it could be the tip is greased up by dirt on the flywheel. Remove it and clean the tip with contactspray and a toothbrush. Easy job, 15min max.
Another option could be the wrong sparkplugs. These engines are very picky when it comes to the right sparkplug. In my '95 480 2.0l I run NGK BP6HS.

[dcw]

Another sensor that commonly goes is the ECU's coolant temp sensor (on front of block). Otherwise my thoughts would also be spark plugs - I agree with B20F that they are critical on these engines (I currently use genuine Volvo and these seem fine).

Silly question maybe, but thinking of other possible obvious culprits have you checked the air filter?

David