My 97 OBS has a slight hesitation/ jerking motion when cold. It usually occurrs upon take off under acceleration. After it warms up it seems to go away. Now this happened a few months back and i used some injector cleaner and it seemed to disappear. It has now returned. It does not happen every single time. Whats the next step.

Do you have the 2.5L engine in that car? Or is it the 2.2?

 

Is your hesitation with light acceleration, or moderate to heavy acceleration?

 

Commuter

It is the 2.2 and it mainly happens with light to moderate acceleration.

I know that the 2.5L of this era runs rich. I'm not sure if the 2.2L has the same issues or not. In general, I have not heard of it.

 

Some of us (including me) have had carbon build up, leading to a hesitation or stumbling when starting off from a light. It is only in the low revs, from idle to (say) 1000 rpm. If you put your foot into it, it acts just fine.

 

I had a MotorVac treatment done on my car and it solved the problem. (These treatments go by various names, usually running $75 to $100.) Over the counter stuff usually doesn't help if the build up is too severe. You could try Seafoam. It seems to do wonderful things. I have no experience with it myself.

 

Personally, I was shocked when the dealer offered up this explanation on my 97 OB (some years back). I do mostly highway driving and would not have expected such a problem with today's fuel injected computer controlled MAF sensing etc etc etc cars. Go figure.

 

I just re-read and noticed that you say only when cold. My problem was regardless of cold or warm. It could be several other things if it is only a situation evident when cold. What lead me down this path was your comment that the fuel injector cleaner seem to help. Let us know what you find out.

 

Commuter