Wife was driving highway speed, without warning 1994 850 turbo just died, no unusual noise, just rolled to stop, recent full tank of gas, where can i look first?

The basic diagnostics will at least tell you what is NOT wrong, if you don't find the problem.

First, timing belt comes to mind since they're mileage-limited. Has yours been replaced within the appropriate service interval? They're usually reliable to last that long. Easy to check. Usually you won't hear any noise when it breaks, except a brief "cching" type noise. That's coincidentally the noise the cash register will make when you get it repaired.

That's the worst of them.

Other common ones are crank sensor, fuel pump, fuses. Any of them are subject to wear and death, and can certainly kill the car immediately. Fuel pumps usually get noisier and noisier, but sometimes they just lock up, overheat, blow the fuse, or whatever. Other fuses get old and blow. You really have to test all the fuses with a light rather than just looking at them to get the real picture of their integrity.

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Chris Herbst, near Chicago, IL. 93 940, 91 240, 90 240, 88 740, 87 240

I'll put my money on a broken timing belt. Easy to check...just take a look inside the cover.

Phil,

Start by checking for any fault codes. From what you have described I'm guessing fuel related problem. A failed fuel pump would make no noise for example. What happened next? Did it start up or did you have to have it towed?

we towed it off the highway, checked codes - one about the evaporator and another about idle fuel mix.

Like mentioned in yet another recent thread here, the problem needs to be properly diagnosed. Check for fuel pressure (using guage), spark, injector pulses ASSUMING there's no codes or something else more obvious, unlikely.

People here can guess away all day but it'll still need proper diagnosis if you want it fixed w/o guessing at expensive parts. An experienced Volvo tech, familiar with 850s should be able to figure it out.