This problem happened to me several months ago, but then seemed to go away. On an older car my first guess would be that the starter is dying or its mounting bolts need to be tightened. But on this sophisticated car I have no idea.

Problem:
If I accidentally do not turn the ignition key firmly all the way to the start engine position KPIII the starter stumbles and the car won't start. What I mean is that if my hand is a bit lazy and I stop turning the key between KPII and KPIII this problem happens. Afterward the 'Service' warning lamp illuminates. Then, the starter frequently stumbles off and on for maybe a week before it finally begins acting normally again.

Weird eh?

-squig

 

Maybe the electrical part of the ignition switch is bad.

 

Thanks for the reply TECH. Is this the part you are referring to?

1993-1997 Volvo 850 Ignition Switch
http://www.fcpgroton.com/product-exe...ategory_id/199

 

Yes it is. Another sign of it going bad is after the car starts the headlights might not be on till you wiggle the key some. Or the ABS light stays on and shift lock does not work till the key is played with.

 

Definitely sounds like the ignition switch. You will need a long torx screw driver to get to the screws to replace the switch.