1990 Lincoln Town Car

DEVBRAVO

MEMBER
1990 LINCOLN TOWN CAR
V8
2WD
AUTOMATIC
130,000 MILES

My 1990 Lincoln Towncar is experiencing some performance problems:
1) sluggish acceleration, pedal sort of "stiff"
"flooring" it doesn't help, I have to give it more throttle gradually. However once it's up to speed,
it accelerates just fine.

2) at low speeds I get this wierd buzzing/vibration
thru the accelerator pedal.

3) When trying to accelerate from a standstill, the
engine will rev up before transmission engages 1st gear (low) however afterthat it upshifts and downshifts just fine.

I've replaced the sparkplugs, plug wires, distributor cap, and rotor.

3 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Check the throttle body, either the TPS is NG, or the cable has a burr and thats why it's tight, or harder to push. Or the throttle plate/shaft is bent.

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Monday, September 14th, 2009 AT 4:48 PM

DEVBRAVO

MEMBER
9 POSTS

Thanks for you quick repsonse.
I assume I can visually inspect the throttle plate & shaft.

Is there any effective way to test the TPS?

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Monday, September 14th, 2009 AT 4:58 PM

MERLIN2021

MECHANIC
17,250 POSTS

There are a few ways, the easiest is to use an ohm meter and unplug the sensor, then attach the probes to the leads on the sensor, move the throttle by hand and watch the meter, it should move smoothly, no jerking on the meter! The other possibility is a vacuum leak. Get a can of spray Throttle body cleaner, start the car and spray around, pay attention to vacuum lines and manifold, if the idle changes, you found a leak. You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!

The other possibilty is the idle air control, it, s bolted to the side of the throttle body.

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Tuesday, September 22nd, 2009 AT 4:54 PM