Idle Bouncing Upand Down after Rev Up.

Post by **shiloh51933** » 20 Feb 2011, 07:25

I just did a full tune up(spark plugs/wires, cap/rotor,oil/filter), replaced alternator/battery and the MAF sensor I had to replace with a new one. She runs but on start up and if you rev up the idle it comes down to near stall then goes up/down, up/down then steady. Now I searched up my make/model 96' 850GLT N/A; I seen the the ECT or MAF were like most common besides bad vacuum or even possible bad PCV system. The MAF is new, I didn't see any hoses disconnected and I have everything to do the PCV system but I don't thinks it's that anyway. The only trouble code my scanner recorded is the SAS(secondary air system), I replaced the check valve, solenoid and the valve in that skinny hosing from solenoid to check valve. I'm sure the SAS has nothing to do with this idle jumping. I'm gonna mess around with her again today, even though it's windy as hell.

Post by **jblackburn** » 20 Feb 2011, 09:22

Saw your post here and replied to that one:
https://www.matthewsvolvosite.com/forums ... =1&t=35221

Let us know if that turns out any results for you.

Pcar · Post by **Pcar** » 02 Mar 2011, 13:19

Success !!! I have a '99 xc70 that had an erratic idle for the past 3 months. Sometimes as much as 1000 rpm variation in park or neutral once the car was warmed up . Did a tune up ,cleaned the MAF to no avail . Took it to Volvo and they said a new throttle body ( $1200 ) was needed. So I took it to an independent to have my throttle cleaned as suggested by this site. The car now purrs like a kitten and the idle is as stable as a rock. Thank you all who made suggestions . You saved me a $1000. And now a warning to all those like me who are new to this site. Do your research , ask questions and try all the simple inexpensive suggestions first. Members of this forum have been very gracious with there advice and I really appreciate it. The irony is if I had taken Volvos word for it and changed my throttle body ,it would have fixed the problem and they would have said " We were right, you did need a new throttle body" , when all it needed was a cleaning.

Thanks again , Mike

Post by **shiloh51933** » 02 Mar 2011, 17:30

Good stuff, it turns out I had to resolve some other things first to get the code for the 02, even though after all the other things(sparks plugs/wires, MAF, SAS-check valve-relay-solenoid/solenoid valve, cap/rotor, alternator/battery, oil change/filter, coolant drain/fill, temp sensor). After doing all that the code for the oxygen sensor could be read by my scanner, reason for the code not showing is because the SAS is related to exhaust/emissions systems and was throwing that code until I cleared it. I know it's confusing but this is what was going on, it's alright though cause I got this ride for just about nothing and I knew it would need alot of the Bullshyt but the block is solid with under a 100 thou, tranny is solid and she's clean.