Hi.

I bought this car a couple of months ago. 160k miles. Really, really love it, but, during the summer, after driving it about 1200 miles, it started bucking on a trip up to Vermont (in the mountains). Not a hot day and not a cool one. Sunny skies.

We'd just refilled, so I pulled off at the next exit and got some dry gas. Put it in the tank, started it up, and all was good.

Everything was fine for the next 1000 miles or so (we travelled a lot this summer). Then, while dropping my daughter off at Oberlin (can anyone say "empty nest syndrome"?), the same thing happened on a cool, cloudy day. No mountains in Oberlin. Kansas might be flatter.

I brought it to a guy in town, there, who works on older foreign vehicles and he said that intermittent problems like this are hard to diagnose. Sorry. Said the engine and turbo look good in idle and that it'll eventually manifest itself to the point where we know what it is.

We've had this occur a couple of times since. Each time, after shutting down the engine and waiting for 15 minutes, the problem no longer exists. Runs like a top (I love the ride on this car).

I mentioned this to my mechanic, who said it might be the fuel pump relay sensor. Checked it out on line and came up with this, which is similar, but about stalling:

http://www.davebarton.com/volvorelays.html

I'm wondering if anyone has a take on this one? Two things to keep in mind which may or may not be relevant:

> Just prior to the Vermont trip (after traveling about 1000 miles with no incident), my friend and I were checking the hoses and noticed that the PCV valve hose nipple was filthy. The nipple on it broke when I took it out, but my friend (Lou) is very resourceful: he splayed a braided tube, wired it tight around the nipple area, and epoxied it in a big way. Put it back in and it ran great. I'm wondering, though, if this might have had anything to do with the problem? I've since ordered and installed a new nipple and had no problems...but that's only been for the past 100 miles or so.

> When the bucking occurs, the car can still be driven up to about 55mph, so long as you don't accelerate the engine into the turbo zone (the white on the gauge). It's only when the turbo is engaged that this occurs.

We checked all the hoses, btw. Nothing collapsed. Everything looks good on that front.

Thanks for your time.

Bob