I have a '97 with manual trans I just bought. When upshifting, the revs hang for a few beats before they drop. This means smooth shifts aren't possible unless I do so very slowly. Also, when driving down the road and releasing the throttle, it takes about 2 seconds for the revs to drop and get some engine braking.

This kind of sucks because prior to replacing a faulty idle air control valve, upshifts were quick and smooth. I cleaned the throttle body (without removing) and made sure the throttle cable, etc were all working right. I even disconnected the battery for an hour in an attempt to reset the computer. Any ideas? Air leak? Normal behavior? (I don't think so)

my T5R does the exact same thing. Really annoying between 1st-2nd, revs just dont want to drop down for a second or two. I have driven another T5R manual and this had the same feel. I put it down to this is how Volvos are in manuals??? I hope im wrong but i have resigned to it being a volvo manual trait.

I actually had the opposite problem: revs would drop like a rock, especially between 1st to 2nd gear shifts. The result, for me, was a very intermittent engine stumble when I let off the clutch pedal during casual, around-town driving.

I had been to the dealer several times about it. Each time, the mechanic was unable to replicate the stumbling problem when I went on a test drive with them. I was convinced that it was a programming problem, but at this point the car is out of warranty. (Be aware that my car uses the drive-by-wire, electronic throttle control system. Hence, my assumption about a programming problem.)

Last week, I was considering IPD's ECU upgrade as a possible solution to this drivability problem. It would be an expensive way to fix a problem that may well have been designed into the car, but I thought it might save me the trouble and expense of trading up to a car that drives properly. While browsing IPD's site, I found this:

http://www.ipdusa.com/pdf/wastegate_adjustment_94_02_turbo.pdf

I tried it this weekend.

Interestingly enough, my wastegate had the base setting at 3 psi, rather than the 1.5 psi that IPD thought that it would. But the adjustment is easy enough, so I tried kicking it up to 4.5 psi. This seems to have increased part throttle torque and responsiveness, and *I think* that I'm also seeing the revs drop more slowly than they used to. I haven't yet had one of those annoying engine stumbles, although it's a little too soon to be sure that it's gone. (Fix on Saturday -- it's Monday as I write this.) But the wastegate adjustment seems to affect the rev drop between shifts as a by-product of the base-boost level.

I bring all of this up to encourage you to try a similar adjustment. Get a pressure gauge and a hand-pump -- a "Mityvac" hand-pump works well for this, see http://www.mityvac.com/ -- and get a baseline measurement for your current wastegate "base setting." If it's up considerably higher than the 1.5 psi that IPD says it should be, or the 3 psi that I found as a base setting, then try LOWERING it with the locknut and adjuster. Hopefully, it will have the opposite effect of what I was after (and may have attained).

Good luck with it. Please let the forum know if this helped, because you're not the first ones to post about such problems.
--
Jim Rothe, '99 S70 T5M,
http://www.jimrothe.com/volvo/index.html

Aaaaahhhh... well, that certainly limits the range of adjustability then, doesn't it? :)

I don't know that intake system, but an older Bosch L-Jetronic system that I get to play with from time to time has a device called a dashpot. Basically, it's a shock-absorber for the throttle plates, and it's adjustable. Any chance that there's a similar device on your normally-aspirated car?


--
Jim Rothe, '99 S70 T5M,
http://www.jimrothe.com/volvo/index.html

Nothing like that on mine. I think it is Motronic. There is a non-adjustable throttle position sensor in the throttle body and the idle air control valve, also non-adjustable. I may put the bad idle air control valve back in and see if all of a sudden I have smooth upshifts with no 2 second wait before the revs drop.