Car Stalls when idle?

Question

I have a 99 mercury sable and anytime my car sits idle like when i'm at a red light or waiting for my chance to turn it starts to "knock" and shake real bad then it stalls, it drives fine at high sppeds and everything but if i put in in park or sit idle for any period of time it stalls

Answer 1

Check your intake piping for leaks; if you find any seal with duct-tape and see if the car improves.

Otherwise you might have a bad balancer

Answer 2

The idle speed cannot be adjusted on this vehicle so that is not your problem. It's possible the IAC (Idle air control) motor is going bad or the pathway is partially blocked. This could be your problem because when driving, the throttle plate is partially open bypassing the IAC, but when at rest, the ECM takes control of the air entering the engine through the IAC to control idle

Someone else mentioned the EGR and this could cause that problem as well. If the EGR is not fully closed and allowing exhaust gases to enter the engine while idling, it can cause this problem. More often, the diaphragm in the EGR ruptures, broken vacuum line and it doesn't open at all causing a NOx problem during emissions testing.

Answer 3

Assuming this is gasoline injected, the first ingredient i'd do is carefully sparkling the throttle plate and bore with a toothbrush and companion and youngsters spray cleansing fluid. Carbon builds up all around the back and front aspect of the throttle plate which hinders the loose flow of air around the plate at idle. also sparkling the Idle Air administration (IAC) valve that the computer controls to keep your idle round 750 RPM at warm idle. note that the engine does no longer stall after a chilly start up at the same time as the idle speed is held higher by using the computer. for sure you commonly opt to envision all of your hardship-free music up products like plugs, wires, cap, rotor, air clear out and so on.

Answer 4

This sounds like it could be a vacuum leak.hoses that come off the engine ,some are used to control the heating and cooling valves ect.You can check this theory by squeezing each hose with a pair of needle nose pliers,if the engine idle goes higher when you squeeze one its probably got a leak follow that line and fix it.Hopefully thats the problem good luck.

Answer 5

Those cars in that year had EGR system problems. Don't know if it's affecting your idle or not. The plug wires should be changed if there still original. Other then that start with a tune -up and filters to eliminate the common problems first.

Answer 6

Your idle is likely set to low (not revving the engine enough to keep it running in an idle state). A tune up or anyone who knows their way around an engine can fix this very quickly.

Answer 7

I'd start with a set of plugs and checking the throttle plate for a buildup of gunk and carbon.

After that, check out the rest of your secondary ignition (wires, coils, etc) and then look for vacuum leaks.

There are a lot of other things that could cause this, but these are common and a person with average mechanical ability should be able to handle these.

Answer 8

the guy is right about the idle set too low. Also your oxygen sensors could be going bad. I had a 96' mercury mysitque and the same problem happened while the sensors were going bad.

Answer 9

Sounds like your idle speed needs to be adjusted. Maybe time for a tune up.

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Answer 10

I had exactly the same thing happen to me in my corolla I ended up going to the mechanics $150. but worth it! i had no power going to through to the idle,plus i had air leaking in one of my valves. sooo much better now.