98 ACTING STRANGE

1998 Mercury Mystique

Tiny

Scotty27

January, 17, 2012 AT 9:38 PM

OK heres what going on. 2.5l v6 automatic. This just started happening, Transmission has only 20k on rebuild, So far I did a fluid flush, changed vehicle speed sensor, and idle air control valve. Its better but it will not shift or very hard when its cold out (below 35 F) once its warmed up, its perfect. Now after driving on the highway at 55-60mph rpms around 2250 for 15 minutes, the torque converter will disengage from lockup and rpms will go from 2250 to about 2700 at 55-60 mph. Try to stop and the car downshifts like a truck, not smooth at all. And try to stop and the car pushes you like your on the gas. Start to drive again and it wont shift, you have to let off the gas like your using a manual trans. Now stop again put it in neutral and rpms go about 3500. Shut the car off, put it in park, restart and you can drive away and the trans shifts like a dream until it decides to act up again. I think its electrical

Im out of ideas, im thinking of trying the transmission speed sensor and possibly the range sensor to see if thats bad. After that im lost. I cant afford a shop, I work part time but I did take it to one and there are no codes at all.

Any ideas, please help before I lose my trans or something.

Thank you,
Scott

37 Answers

Tiny

rivermikerat

January, 18, 2012 AT 8:38 AM

Take it to a shop that will scan for soft codes. These won't set the CEL. It may be a shift solenoid.

Tiny

Scotty27

January, 18, 2012 AT 7:34 PM

When the shop looked at it the only thing they found was the vss was bad. He said they could not find any thing else.

Tiny

Scotty27

January, 18, 2012 AT 7:35 PM

They told me it was some thing electrical. They said definitely a sensor.

Tiny

rivermikerat

January, 18, 2012 AT 7:53 PM

That could do it. Incorrect signals from the vehicle speed sensor can and will make the transmission shift incorrectly.

Tiny

Scotty27

January, 18, 2012 AT 9:52 PM

The VSS was replaced, as well as the idle air control valve.

I am also thinking could it be the throttle position sensor or the transmission speed sensor?

Thanks, scott

Tiny

rivermikerat

January, 18, 2012 AT 10:07 PM

I don't think it would be the TPS. Maybe the transmission range sensor or the turbine speed sensor.

Tiny

Scotty27

January, 18, 2012 AT 10:38 PM

Just got my trans speed sensor. Going to put it in and see what happens.

Tiny

rivermikerat

January, 18, 2012 AT 11:21 PM

Ok. Let us know.

Tiny

Scotty27

January, 19, 2012 AT 12:25 AM

No, did not fix the problem, its worse with it in there. And the car pushes you like your pushing on the gas until you come to a complete stop. Than it downshifts from 2nd to first and everything returns to normal until you drive it again.

Tiny

rivermikerat

January, 19, 2012 AT 4:11 AM

I've asked some colleagues to peek in and see what they think.

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