Cadillac Repair: 6.0 liter engine, engine management systems, cadillac coupe de ville

Question
QUESTION: purchased cadillac coupe de ville in need of engine swap.replacing engine with same factory motor.need advice on how to ensure proper operation and safegaurd against early problems.have researched engeine and found problems with computer control etc.any advice on how to keep this car running like new?thanks signed, glassman

ANSWER: If you replace it with the IDENTICAL engine. You may have to make some small adjustments.

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QUESTION: i have purchased identical engine.my question is refering to engine management systems and any unforseen problems that i can avoid.is it possibly better to have the engine run on all eight cylinders all the time?do you know of any competer management system upgrades.thanx

ANSWER: What YEAR vehicle ?

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QUESTION: 1981 coupe de ville

Answer
You have the 8-6-4 engine which has had it's problems, as vibration when in 6 cylinder mode which is NORMAL and lack of power when in 4 cylinder mode which is normal. Just make sure that the MAP and BARO sensors are changed over to the new flat black plastic sensors instead of the old round metal canister style  and make sure that the MAP sensor has been relocated into the engine compartment from behind the passengers right side AC vent as condensation tends to build up in the MAP rubber line causising engine mis-firing .