Hello everyone,

I'm new to this forum and have a few questions. I have this Cadillac Fleetwood, while driving it after it gets warmed up it just stops running, i can coast in neutral and turn it over, it still won't start. Once i get the the curb and let it sit for a few seconds it refires. I put my Snap on scanner on it today and drove it up the highway, of course it stalled and there were no codes. The speedometer doesnt work on it, so i should take it that the speed sensor is faulty? Will the speed sensor cause the car to shut off at a certain RPM if it is faulty? Running in the garage it runs great, wont stall or stumble, but driving it is when it happens. I sure would appreciate everyone's thoughts on this, it's driving me nuts.

Thank you,
Sellncars

Check the power terminals in the fuse box underhood, that has been known to be a problem in many of the B bodies. The Fleetwood is a D Body, but they are related.

Look for it to be loose or corroded. The replacement terminal is brass, I think the factory one was aluminum.

Egr?

EGR won't stall it when driving, only when at idle and it goes full tilt on.

It almost strikes me as the injectors are shutting off or PCM is shutting off, as there are no codes. Any other issue will report a code.

SellnCars, where are you located?

SellnCars, where are you located?

I live in Upstate, NY.

EGR won't stall it when driving, only when at idle and it goes full tilt on.

It almost strikes me as the injectors are shutting off or PCM is shutting off, as there are no codes. Any other issue will report a code.

I would agree with the fuel shut off, or ignition shut off. Kind of hard though to check spark and fuel while driving. That would definately tell me where to look first.

Any ideas how many miles on the Optispark? Check the coil, coil to distributor wire, the Opti connectors and make sure the opti vent is working properly too.

My $0.02:
I have to wonder if it's a clogging fuel filter. What you describe is almost exactly what our 76 GTO did when the fuel filter clogged.
(You run it, it sucks all the fuel it can until the line is dry. Then it craps out. When you sit a while everything is fine until it sucks the line dry again.)
The way I found it was the filter was on my way home after work and on the interstate it suddenly had a "governor" on it. I couldn't go over 45!:eek:
Soon after the car would quit, completely.
Replacing the fuel filter cured the problem.:thumbsup:

I think Rick is on the right track. Fuel related issue.
I would suspect the fuel filter or the fuel pump on its way out and providing insufficient pressure.
If you hook up a fuel pressure gauge and take a reading at idle you should be around 37psi. If you remove the black vacuum tube from fuel press regulator the psi should jump to 43-ish psi (no more than 48psi).

I'd tape the gauge to the windshield and go for a ride somewhere and see if it drops off while cruising around.