Just a tad bit of Hesitation

[Stratox]

I've had an issue for some time, almost two years now that not too many people and or dealers or independent techs can help me with.


Right around 1900-2200 RPMs' at any speed (mostly highway), it feels like my car is losing a bit of "steam" and just hangs and slowly builds up speed when trying to accelerate.

I've had the spark plugs changed from NGK back to stock Volvo, back to NGK (prefered), coil packs all swapped and new. Still this issue. Usually, the small electronic Display says I get around 284 miles per tank of gas, not its always around 300-322 miles.

I have to activate the overdrive or step up to get the car out of this hesitation on the freeway.

Thanks for reading my looooooooong question/post!

Cheers!

[azatoglu]

When I have my 1997 S70 T5 I had the same issue and couldn't solve it either.I changed almost everything you mentioned and more , still I can see the rpm dropping slightly in that power range.Then I found some tech docs in Vadis stating that in fact this is a normal behavior of the transmission which some how locks to an inner piece and continue to accelerate.I was only having this when I am in cruising speeds.

[Stratox]

I was thinking of something along those lines as well. I couldn't find any docs that stated that for my type but it seems to appear "out of the blue". As soon as the computer said I could go 300 plus miles on a tank of gas when previously I could go to 280 ish; this occurred.

I'm not too worried about the acceleration, worried more about the mileage increase?

Is there a sensor that is tied to this that might need to be replaced?

[IPD-Donovan]

It is normal behavior for the torque converter to hold the RPM where the car can most efficiently produce the torque necessary to accelerate. If you press the gas more rapidly or press the pedal farther the car should downshift a gear or two.

[Stratox]

Thanks, I'll have to experiment with that.