: Miss or Studder around 45-50

11-17-04, 06:04 AM
I noticed that I get a what seems to be a slight miss when crusing around 45-50 mph. It happens after the Torque Converter engages. It almost as if its not fully engaged or is going in and out. If you watch the tach you can see it move up and down ever so slightly, like maybe 50-100 rpm or so. I dont know if its a miss or in the tranny. 98 concours 141,000. The plugs and wires have about 40,000 miles on them.

11-17-04, 05:39 PM
Hmm, that sounds suspiciously like my problem but I can get it at lower speeds as well. It is just much more noticable at higher speeds in OD with the TCC engaged. I am suspecting wires in my case.

Fantom Infinity
11-19-04, 12:16 AM
I get the 45-50 MPH stutter as well, happens mostly when I'm going up an incline.

11-19-04, 01:19 AM
It is somewhat normal to get a very light shudder or chuggle feel at 45-50 at light throttle openings. That is the worst case situation for low engine RPM, lots of EGR for fuel economy, a locked up torque converter for efficiency, etc.... To the engineers it is the "feel of fuel economy"....to the customer it is an annoyance. It is a fine line to make the system as efficient as possible, isolate any pertubations in the driveline and eliminate any feel of chuggle. Unfortunately, depending on the car and the road and the conditions a slight amount of chuggle will sometimes come thru. It could be perfectly normal.

One thing you can do is to hold the throttle constant when you are feeling the disturbance and reach for the brake pedal with your left foot. While holding the accelerator constant LIGHTLY depress the brake pedal just enough to engage the brake switch which will disengage the torque converter clutch via the brake interlock. If the roughness goes away totally then it is likely just the "normal" chuggle associated with the locked up torque converter.

Since you are not seeing any check engine lights ( the engine misfire diagnostic is not setting) I would think that the engine is running fine and nothing is wrong. Especially if you can make the roughness go away by momentarily disabling the torque converter clutch. The clutch really accents any driveline roughness with can come from engine torque pertubations as mentioned or even from road induced roughness telegraphing back to the engine thru the driveaxles and transmission. Sometimes the phenomenon is almost totally un-noticeable on normal roads and then it will be evident on very smooth pavement. Lots more chuggle complaints from Florida where the roads are very smooth. Not many chuggle complaints from Michigan as it is impossible to feel for the potholes.

11-19-04, 06:22 PM
I mentioned in a earlier post that my problem was similar. Stuttering but idling fine. My wires and plugs had 30K on them. 2 of my wire caps had "walked" up the plug slightly and must have been causing a gap. As soon as I reseated all of them, no more stutter. Been fine now for 600 miles.

11-20-04, 07:42 PM
You are correct that the chuggle goes away when I press the brake pedal and make the torque converter diengage. And it's only apparent at barley open throttle. Thanks for the insight. 98 concours 143000