94’ shakes when going uphill

[Meghan]

Whenever Im going uphill, the car begins to shake until I shift from overdrive to drive, then once Im over the hill I can shift back to overdrive. Is there a fix to this?

[J Wikoff]

I'm thinking that's a torque converter clutch problem. Maybe the vacuum modulator. The later is a cheap easy fix, if so. If you take the modulator off, and tip the vacuum port down and fluid leaks out, it's definitely bad. There's just one bolt and a vacuum line to remove. Many new modulators are like $20 and are adjustable. It can still be weak even if it doesn't bleed on you.

I don't remember how to diagnose the torque converter clutch.

[RJolly87]

Shaking could be caused by a number of things, including a misfire. My 93 park Avenue also had an issue I never tracked down that caused it to never downshift out of overdrive with cruise control engaged, even when slowed below 45mph, which the pcm should never allow.

Is this the same car that is dead in your other post?

[RJolly87]

My 94 Regal also developed a misfire that became apparent under load, and would shake the car violently when it happened and the torque converter clutch was locked up.

[harofreak00]

I agree that its a misfire, and its so minimal that you're only feeling it when the torque convert is locked up.

If you have a way to access live data you could see which cylinder is misfiring (I know its extremely difficult with a 94 and the OBD1.5 system). If its due for plugs and wires I'd start there. Otherwise replace the ignition coils with a set from the junkyard.

[96 SSEi]

does the check engine light flash when it shakes?

[RJolly87]

does the check engine light flash when it shakes?

This vehicle will not do this. This behavior didn't start until OBD 2 in 1996.