Cadillac Repair/shaking


when im driving my 93 cadillac seville and im going 45mph it starts shaking and stops after 50mph. what could be causing this and how can i fix it? thanks


Unfortunately, a problem like this cannot be fixed over the internet and requires a tech driving the vehicle to understand the symptom you are referring to. You do not want to take the car to a dealer because most of the time from my experience will replace parts for as long as you have money in your wallet and the problem does not get rectified anyway.

Find a reputable service center in your area. The engine may require to be scoped, or the computer system tested. Your complaint does noy have a common fix. This is merely a symptom that could a vast array of potential issues. In fact, be wary in your situation if someone tries to tell you to start replacing parts without being at the vehicle, because it is obvious they have no clue as to what is wrong with your car.

This can be as simple as a bad plug or wire. I have found it very common on these cars with transversed mounted engines in which the front bank of plugs may be changed, but because of the difficulty of access to the rear 4 plugs, they don't get replaced.

I had a 454 CI Suburban that began running similar to your complaint. The truck had 190,000 miles on it. I began with the simple stuff first. I decided to check the plugs. I found that there was very little electrode left on at least 3 spark plugs. The plugs were original and had never been changed! I replaced them and went to the distributor. I I removed the rotor which was severely burned and carbon tracks in the capI changed the rotor and cap, and couldn't get the cap back on. The distributor bushings were worn out and I had to replace the distributor. I then replaced the wires. When I was all done, the engine ran very nice. Stalling and misfires were gone.

I don't want you guessing on what to replace and even a $50 or $75 diagnostic fee is well worth it and this fee is commonly picked up by the garage if they are doing the repair.

Let me know what the problem ends up being.

Good luck!

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Rob Painter


Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?


Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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