1993 3.3L stalling at stop or light

I have a 1993 century with a 3.3L, that keeps stalling at stop signs and lights. I have replace that wires and plugs. It also backfires through the air filter. If I have it in park it will stay on all day with out cutting off, once I put in drive and step on the gas it will backfire and take off, I come to a light and it will idle down cut off but will start right up again. If it cold it will not idle high. NEED HELP PLEASE!

Step ONE: Check and clean or replace your IAC valve. This valve will cause you to run lean if stuck open and it also will affect your idle speed especially when cold. Good Luck.

Well I changed the IAC and still does the same thing. Now I get a code 23 TPS. I chenged it and still the same. I am going to shot this buick! anyone has any other ideas of what it could be.

Vacuum leaks could cause a stall. Vacuum leaks can come from many places. This includes the brake booster and a number of vacuum hoses.

Do the easy stuff first:

PCV valve
Air filter
Fuel filter
Visual inspection of ALL hoses

Then go from there............

Hummmmm, you said it was running lean, starved for air.

How many miles is on the car?

I agree about the vacuum leak. You can check for a vacuum leak with a vacuum gauge. You can loan one for free at a lot of parts stores. A Haynes or Chilton manual will have instructions. Good Luck.

Just bought a buick century limited and I'am having the same issues with mine as th other guy. The stupid thing keeps dying when I come to a stop when the car is in drive. But never when in park. Unfortunetly I havn't been able to put her on a lift and take a look from underneith her as of yet to look for hose damage from the underside, but the hoses from the top look fine. Please help!!

common vacume leak source is near PCV valve (location: passenger side underneath alternator)

I change the Igen coil and that was the problem.

common vacume leak source is near PCV valve (location: passenger side underneath alternator)


Thanks, I'll try that and let you kno if it worked.

I have a 1991 Century and had the same problem. Turned out to be a bad oxygen sensor. You may want to consider replacing it.