1989 Park Avenue 3800 Suddenly Runs Rough

[RandyM]

I "inherited" this '89 Park Avenue from my father-in-law a year ago. Ran fine until yesterday. Stopped on an errand after work, got in and started it, then it ran rough. Has run rough since. Runs like there's no power or not firing on all cylinders. Doesn't matter if it's hot or cold. Someone suggested a coil or fuel pump. On idle, it'll sometimes die if I let my foot off the gas. Reading the posts here, I'm inclined to believe it's electrical, but I'm not a mechanic nor do I play one on TV! <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

I'm not opposed to replacing my own parts and have been known to do so, but if it gets too involved, I'll have to find a reliable, honest mechanic somewhere in Des Moines.

Any thoughts?

--Randy

[Gene Brink]

Randy,

I'd bet electrical. Try pulling plug wires, in twos - both from the same section of the coil pack, until there isn't any change in how the engine runs to determine which cylinders are not getting spark. It will either be the coil pack or ignition module (and I'd bet the ignition module is bad). Both can be tested if you pull and take into Auto Zone (or others I'm sure) for no charge. A quick $60 or so for a shop to plug into their computer.

Good luck

P.S. Remember if you are not getting spark the raw fuel is still be injected into those cylinders so you will quickly contaminate the oil as well as really stressing your catalytic converter with the very rich exhaust flow so do not drive much this way.

[Centurion]

Randy, my first guess would be the crankshaft positioning sensor. Your symptoms sound very similar to those I experienced with my '89 LeSabre when the sensor went bad. It's a fairly inexpensive part, and I'll bet that someone on the forum here has replaced one. If not, a mechanic having some 3800 engine experience can probably fix you up in short order.

[shoreice]

Try the Reatta forum, all have 3800s and all 88-91. Oh,yeah, most have problems solved by forum members.

[Guest BJM]

Vacuum leaks, electrical interruption (coils/plugs) sensor malfunction not as likely if it is running. Also check how long is it cranking prior to starting ?

[JohnD1956]

Take the coil packs off, and then the spark control module. Look underneath the SCM for corrosion. If you find any corrosion, continue to take the coil bracket apart and lightly sand each mating surface including the bottom of the spark control module. See the attachment from my 95 Riviera.