1998 Mercury Mystique Bucking

KARISBSW

MEMBER
1998 MERCURY MYSTIQUE
6 CYL
FWD
AUTOMATIC
113,000 MILES

I recently bought this car and it drove well during the test drive (of course) but within a matter of days it has started bucking very badly when it shifts. It doesn't seem to matter if I'm going up or down hill, fast or slow. The RPMS seem to run at either 1 or between 4 and 5. There are no Used Car lemon laws in my state so I'm hoping I don't need a new transmission. Could this be caused because it needs a transmission flush?

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Hi Karisbsw and TY for the donation

Do you have a check engine light and when was your last tune-up-don't recall consider one immediately. An engine needing a tune-up will affect how the transmission operates-Flushing it might make things worst than it is I don't recommend it. If its slipping get it pressure tested could be a shift solenoid/s If its not coming from the transmission-could be one of the following below:

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)