First i should say I just replaced the cat after having serious power issues. Thanks to anybody that contributed to that one. Now I have noticed a new thing. Well 2 new things actually.

1. When I take my foot off the gas when I'm about to stop, or take it off cause I'm going down hill and don't need it, it feels like it's cutting out. You know, kind of a light jerk, or shudder (I'm not sure how to describe it exactly) It is smooth again when I use the gas pedal again. The fuel filter was replaced in October (I think it was october)

2. I'm having problems with the tach reading when I use overdrive. I'll get up to about 60mph and the tach will be around 2500 then it will just drop to 1800 or so. At times when accellerating it will go up by a few hundred, then immediately drop. Sometimes it wont go back up at all (rarely it does just what it should). I thought at first it was just the needle being faulty but I can hear the difference when it drops. Also my car is louder when it's in overdrive (sounds like it's from transmission but not a huge amount of noise). This does not affect it's ability to increase speed or the ability to maintain speed, and it ONLY happens in overdrive. Any thoughts?

This forum was such a great help when my cat needed replacing.. I'm really hoping somebody can help me out here. Could both issues be from the same thing?
Thanks
Krys.

My car is a 96, with a 3.1, has automatic transmission, and 209,000 miles on it. Things done since August: the transmission has been flushed, the fuel injection system has been cleaned, new fuel filter, new alternator, new battery, new cat, new cv shaft, new bearings.

 

This is a good stumper. I'm thinking the transmission is the problem due to the style - they weren't the strongest, but it could be something simple that I'm not thinking of like a weird PCM or maybe a sensor.

 

i was thinking the pcm also


might see if you can get them to pull codes on it

 

#1 check motor mounts, does it clunk when shifting into drive or reverse while holding the brake?

#2 "about 60mph and the tach will be around 2500 then it will just drop to 1800 or so" possibly normal condition, shifting from 3rd to 4th

"when accellerating it will go up by a few hundred, then immediately drop" possibly normal condition, tcc release when you accel lightly, and then lock up again once load has satilized or decreased.

"car is louder when it's in overdrive" possibly normal condition, if the noise is engine/exhaust noise because the car is under a heavier load, doing as much work at 1800rpm in 4th as it did at 2500rpm in 3rd

 

I should confirm that as well, the Monte should be in 4th gear at 1800 rpm at 60 mph.