Cadillac just started to backfire and stall along with fading when accelerating.

WSARKEES

MEMBER
1970 CADILLAC DEVILLE
V8
AUTOMATIC
70,000 MILES

When accelerating the car has started to fade then when you let up off of the accelerator it will run but as you accelerate again it dies, it backfired several times, and also died in drive, I put it in neutral and it starts right up, it might go for 10 - 15 miles and then the fade starts again or the engine dieing out while in drive.

I am assuming it might be the plugs, plug wires, , maybe it needs a tune up or a distributor cap or all of these, am I close?

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

This isn't a tune up issue. To me, it sounds like the fuel pump is going. Have you checked fuel pump pressure? Also, has the check engine light come on?

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Sunday, August 24th, 2014 AT 9:42 PM

CARADIODOC

MECHANIC
33,873 POSTS

What you're describing, especially the 15 miles, is exactly what happens when the sock on the pickup in the gas tank gets plugged or is collapsing. When it gets bad enough for the engine to stall, before you try to restart it, remove the air filter cover, then work the throttle by hand to see if there's two nice solid streams of gas squirting in. If not, suspect that sock.

A poor man's trick to prove it is to remove the gas cap, remove the incoming fuel hose from the fuel pump, then use compressed air and a blow nozzle to force air into the tank. That will push the sock off the end of the pickup pipe. You'll be left with just the filter in the carburetor but the running problem will be gone.

At that point, if you don't want to drop the tank to replace the sock, you can cut the fuel line before the pump and install a Chrysler filter. Those last the life of the vehicle and you'll likely never have to replace it again.