Jerking/slipping at high speed


#1

Thanks for thoughts in advance…128K 2000 Saab 9-3, had radiator replaced 3 weeks ago. Was driving 2 hours yesterday, had on cruise appx. 70 mph when car started to jerk or slip about 1 hour into the drive. Felt like a lurch but speed was still maintained. Had to return same distance, did not use cruise but had same problem, intentionally varied speed on way home. What could this be and is it time for a new car? Have had some major repairs this last year. Thank you,.


#2

It could be a transmission problem, and engine misfire, or even the brakes grabbing. What does the tachometer do when this occurs?


#3

The Turbo tach also is taking a leap and then levels back as the car does the pulling feeling…was fairly consistant/rhythmatic


#4

Then you are likely having a transmission problem. Automatic or manual?


#5

Manual. Not sure if my other answer posted or not. When does one know when to throw in the towel?


#6

It sounds like your clutch is slipping.


#7

Could also be the O2 sensor going bad. The forward one(s) help the computer determine the fuel mixture at steady speeds. Contaminated ones can lean out the fuel mixture until you have to step on the gas. Then the computer takes the advice of the throttle position sensor. The problem will always repeat.


#8

any of these possibilities worth the price to fix? or is it all downhill from here? i appreciate greatly the postings


#9

That would cause a misfire, which wouldn’t cause the tach to jump.


#10

I agree. Is this the original clutch assembly?


#11

I apologize. This is an automatic transmission. I had a helper on the earlier post and they were confused. This is still the original everything with the exception of the new radiator.


#12

Knowing now that this is an automatic, let me suggest you not drive the car until you have a tranny shop look at it. It sounds like your torque converter clutch isn’t holding. My concern is that when the radiator was changed the tranny cooler was not properly reinstalled (or, if the cooler is in the lower part of the radiator the lines were not properly reconnected, the tranny was not properly refilled, or something of the sort).

In short, there exists a possibility that your radiator change left your tranny fluid low, leaking, or without proper cooling and it’s now cooked. That’d be my initial guess.