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I suggest accessing your 1991 Cadillac Devilles onboard computer and obtaining the fault CODES that are stored in the computer.To do this:

1. Turn ignition switch to the ON position. Do NOT start the engine.

2. Simultaneously push and hold the OFF and WARMER buttons on your Electronic Climate Control panel for 3 seconds and then release them and while watching, you'll see your fuel data display change.

3. On your fuel data display, you will see LETTERS & NUMBERS displayed. Be prepared to write them down. As they run through fairly quickly, I suggest making a column list ahead of time on a piece of paper. Heading each of the four columns in order with these codes, EE And E And FF And F . Then as these codes flash, write down the number displayed under each of these coresponding codes number

Then when it stop's at .7.0 the code's are done.4. Turn ignition switch OFF.Now once you have the error codes, the answer to your question maybe at your finger tips.Good Luck

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NewCheck that none of the wires are touching the exhaust manifold, you can use tie straps to tie the cables so that they are not touching or near an extremely hot surface. You can burn up a wire and cause SERIOUS engine damage, if its been goin on for 2 weeks or so get your front motor mounts checked out, theres a possibility it may have cracked.

Did you change the rotor button as well? This problem your describing really needs to be described in much more detail as to how and when this miss started the more information you can provide is the easiest way for others to understand your situation. , EzForJesus

Is it possible that you inadvertantly tossed out the grounding strap when you replaced the cap? That might be your problem...I would just hit a junk yard and grab another one. It's a cheap way (about $5) to see if that troubleshooting works. If not...the mid to late 80's and newer are known for electrical frustrations with that computerized stuff. Good luck!

You might want to check the timing. I'm not sure how to adjust it but you definitely need to see where it's at. Also how many miles are on it? If it is a lot the timing chain may have stretched and may need replacing.

Make sure that the wires are properly routed to the right cylinders. Also make sure that the wire snaps into place when connecting them both to the spark plugs and the distributor cap. If a wire is not properly seated to the plug or to the distributor cap the cylinder that the wire goes to can fail to fire properly. Believe it or not the voltage that needs to go across the tip of the spark plug is aroung 16k volts, not a whole lot of amperage but it insists it get plenty of volts. Improperly connected wires can realy play havoc with the way the engine runs.

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โˆ™ 2015-07-14 16:03:53
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Q: After changing the spark plugs wires and cap in a 91 Cadillac DeVille what would make it sound like it is still 'missing'?
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