Over the past 6 months, out of the blue, I will be idling at a light then the rpm's will start going up and down then the car will stall. If I'm quick enough and can put it in netural and rev up the engine, things are fine. Good for a month then it starts again. Today it actually stalled and it did not want to start again. Seemed to almost die everytime I tried to give it gas. Finally got it going then - it great again.

Any suggestions what to look for?

Before consenting to replacement of any expensive parts like airflow meters or throttle modules, I would look carefully for an air leak anywhere in the intake system. If a vacuum hose has a crack it may be letting in air under some conditions and not others. This would include the flexible hose from the air cleaner to the throttle body.

I once had such a behavior (not on a Volvo) which turned out to be a cut in the power brake vacuum hose. Sometimes it worked and sometimes not, depending on the flexure of the hose.

Did you get a "check engine" light?

Let's hope that you own a 1998 S70 and do not have an ETM. I had a similar problem with my 1998 V70 T5. My local dealer replaced the air mass flow sensor and the problem resolved. This cost just less than $400. I know this part is available for much less from internet sources. Accurately diagnosing the problem is what I guess I paid for.

Dude, I have the exact same problem, just worse. Did you ever find out what it was. Please reply to my e-mail address listed below.

aron@austin.rr.com

Thank you,

Aron-

You didn't say what model year S70 yours' are. If it's a '99 or '00, it could be the dreaded ETM failure coming on.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon