I have a 1989 Lincoln Towncar with a 5.0L V-8 EFI w/140k miles and have
a problem with missing/shuddering. It started with a few months ago with a
small shudder at idle that occured every 10 to 20 seconds, particularily
when the engine was cold. The shuddering became more frequent and more
pronounced after a while. Now the engine speed goes up and down and shudders
at idle and shudders frequently during normal driving. During acceleration
the shuddering is less noticeable. Also I notice the exhaust has a strong
distinct smell of shoe polish? Is this indicative of anything? Another
strange symptom, when I shut the hood the engine seems to rev up a few
hundred rpm for a couple of seconds. Odd eh?
Here's what I've done so far:
1. I replaced worn/corroded battery cables but that was not the problem.
2. I replaced a alternator and that took car of the flickering headlights
etc but that did not cure the problem.
3. I replaced the fuel filter and that did help high end acceleration but
not the shudder.
4. I replaced the belt tensioner pulley because it was squeaking but did
help the shudder.
5. Dist cap and rotor are less than 2 years old and belden premium spark
plug wires are about 4 years old, so i didn't mess with them.
I looked in my shop manual but unfortunately most of the info concerning
driveability/emmissions is located in another manual called Engine
Some things I am thinking about doing are:
1. Getting a fuel pressure gauge and checking the pressure. There is a
bicycle type valve located in the fuel supply to the injector manifold. Is
this where I check it? What is a typical pressure?
2. My plugs are bosch platinum that are about 2.5 years old with maybe 25k
on them. Maybe I should inspect or replace them?
3. Connecting up the timing light and possibly looking for intermittent
spark on each plug wire.
4. Take it to the dealer and get soaked for major bucks.
Any thoughts or suggestions would be much appreciated.