I have a 98 S70 GLT with 96K miles. Sometimes while driving in suburban chicago traffic and thirty five, or forty five mph, the engine will suddenly go to zero rpm's for perhaps one second and will then resume running normally. On one ten mile trip through heavy traffic it did it eight times. Yet, later that day on the return it did not do it. No check engine light, btw.

It will also do it while idling at a light, or driving slowly, say at five mph. Just this evening, it did it at five mph and the engine did not come back to normal rpm. I had to stop the car, put it in Park and restart it. Restarting the car is normal and fine. In between these odd situations the engine runs smooth as can be and has plenty of power.

Unrelated? to this, two weeks ago, my ignition switch started giving me a lot of resistance as I turned it to start the car. That lasted about five days, but now it's smooth and easy to turn, just as always. About a month ago, I got a lean burn message on the computer, but had the injectors cleaned by a local shop that sprayed a cleaning fluid through the throttle body for half an hour. No recurring computer message.

Has anyone had this happen? What was it and how did you fix it?

thanks,

bob.

i have the same problem with my 98 s70 glt. took my to the dealer and they did $1100 worth of work and it is still doing it.... if you keep the RPM's Up then no stall and when i mean up i am saying anything over 1000rpm.

let me know if the relay works.....

one other thing my car has 96k miles also !!!! could be onto something here !!!

Similiar problem with 850 and the fuel system relay and/or fuel injection relay. Check old messageboards on 850. Might be the same problem.

You mean one of the relays which are in the center console behing the ash tray? That sounds likely doesn't it?

Would it be corroded contacts or sticking contacts? No. More likely a failing magnet/plunger assy in the relay which deactivates while driving for a brief period.

I'll replace it and see what happens. thanks!

A while ago there was some break through on this... an ECM reflash from the dealer to the tune of 150 should smoooth out the engine revs. I have the same issue in my s70 glt 98 141k miles. I also live in chicago and the traffic is a big reason why i get the hesitation alot as well.

Bob, contact me at my e-mail jbieda @ gmail . com

-Joe

i have a update on my problem...... my problem has been fixed it was cause by a faulty mass air meter. when my car was dying on the freeway it would not put anything in the computer. when it was doing it felt like the car would loadup.

hope this helps. now to get the ABS module fixed !!!!!!!! oh yeah and the Squeeky dash !!!!!!!!

I have been experiencing a similar problem. 1998 S70 w/ 63500 miles. Problem started when I had battery replaced. Severe and frequent hesitation for about a week after then it basically went away. Had apt w/ dealer and couldn't replicate the problem. Now it seems to occur when I let up on the gas and some idle control takes over. Drive along for miles and let up on the gas slightly as if to just hold your speed and wham - hesitation then recovery. Could it bethe idle air control valve? or the mass airflow sensor or maybe the throttle switch. So far all the advice I have received has been to clean all the connections and hope it goes away - or gets worse so it can be diagnosed. Anybody have experience with an actual fix?