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I hope someone can help, I have a 1985 Fleetwood Brougham 4.1 The car when driven "normally" feels like it has mis-fire, however when driven hard this mis-fire seems to go away. It seems like it is greatly affected by temperature and humidity. Hot temp and high humidity it runs like it only has five cylinders, cool temp like in the fall it runs "almost" perfectly. cold temp like below zero C. chugs gas at a frightening rate. I have put new Oxygen, Baro and MAP sensors as well as plugs, wires and rotor cap. The only code which sometimes comes up, after driving at steady speed for some time is code 39 TCC engagement problem. Car otherwise runs great, hope someone can help as it will soon be going away for the winter.
 

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90 Brougham 5.7, 05 Deville DTS
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About a month a go I had similar problems with my 4100 85 FWB.

Check the firing order on the plugs and make sure it is correct. Also the gap on the plugs should be .060. Also check you vaccum lines, make sure they are connected and none of the lines are rotted.
 

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90 Brougham 5.7, 05 Deville DTS
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If you already didn't do so, change the pcv valve and crank vent filter (the one in rear of the air cleaner case on passenger side).

Another suggestion have the transmission check and serviced, because the code 39 could be causing you to have tranny problems.

Good luck, and let us know what the problem was.
 

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Discussion Starter #5
Thankyou for the suggestions, it will give me something to look at over the winter months while car is away for the winter. I appreciate the advice
 

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70 Fleetwood, 87 and 90 Brougham, 94 Fleetwood
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The code 39 is a clue. These cars with the THM200 4R tarnsmission have a problem with the torque convertor clutch remaining engaged. This can feel like driving a standard transmission equipped car at low speeds in top gear. It will have no power and can buck and jerk, even stalling at times when you come to a stop. It also requires you to drive heavily into the throttle to try and get some motivation, which can lead to excessive fuel consumption.

But, the fix is simple. The solenoid is usually the problem and it can easily be accessed once the trans pan has been removed. It is located at the forward end of the valve body. The part is about $50. It will also give you the excuse to change the oil and filter.

Mike
 
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