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Discussion Starter #1 (Edited)
I have a 1993 LeSabre Limited with a 3800 Series I. Recently I have been experiencing poor acceleration and an intermittent rough idle. I have replaced the following:

Fuel Pump,
Sending Unit,
Trans Vacuum Modulator,
Mass Airflow Sensor,
Fuel Pressure Regulator,
Intake Manifold Gaskets,
Spark Plugs and wires,
Tested coil packs (All work),
Vacuum Lines,
and Air Filter.

When I bought the car it ran ok, it just had a bad fuel sending unit (The gas gauge always read full) so I had the fuel pump replaced while the mechanic was in the gas tank just for good measure. The car ran fine. I replaced the spark plugs later and it started misfiring and I soon realized that one was loose (I made a goof). I fixed it and the Car ran ok. Recently it started idling weird and has low power
while accelerating. After troubleshooting and replacing over $400 worth of parts ( Mass Airflow Sensor, Fuel Pressure Regulator, Intake Manifold Gaskets, EGR, and Vacuum Lines) it still acts weird. After replacing the Fuel pressure regulator and intake manifold gasket it seemed to help a small bit, but still doesn't perform as it should. I am frustrated and at a loss for what to do, I am worried that eventually it will turn into something worse and I really can't afford to do anymore to it :(

Any ideas or advice?


1,099 Posts
Really sorry to hear of your frustration. We had a 95 transport series 1 that had trouble with the idle from time to time over the years.

1) Unplug the MAF, and drive without a heavy load on vehicle..20 mph. - Your new MAF may have become faulty.

If no help

2) Re-check ignition wires- use di-electric grease at tip only of coil pack and spark plug terminals. CHeck with another known good wire if possible on each plug( may possible have broken wire internal )

3) Spray carb cleaner, brake cleaner, etc around intake and vcacuum lines, etc.. and check for changing of idle- vacuum leaks

4) Check the fuel pressure at the shraeder valve on the fule rail with a gauge. Fuel pressure should be at least 40 lbs non supercharged.

Less Likely- I have replaced the coil packs from a used set from Ebay, and helped smooth a rough idle. THere never was a loss of power though.

THese are just some first steps to try.

Best of luck

866 Posts
Hummmm, you could have a bad/corroded spark plug WIRE/CONNECTOR. If you have an ohm meter, you can unplug one wire at a time and see what that wire has for resistance. New/good wires generally have less than 15,000 ohms resistance. If a lot higher, replace them all and make sure the correct coil terminal is connected to the correct spark plug. Another thing that happens to plug wires is the metal connector inside the boot at spark plug end or coil end can get rusted or corroded causing poor voltage to the plug which will result in bad/weak or no spark. Reading your post makes me think of either a bad wire or two, and weak coil pack(pretty common back on the older 3800's), and a cracked spark plug. If you have a local repair shop that has a "scope", they would be able to see these types of problems immediately. I would find the problem before spending more $........... Jake
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