1996 Town Car silently shuts off when slowing down/coming to a stop.

[mnmlnomad]

I have no idea what's going on but as the title says my 96 Town Car dies on me when I'm coming to a stop or just slowing down, whenever I try to accelerate the pedal seems dead and I have to restart the car. I have taken it to several specialists, changed out many different parts and sunk too much money into it, my car only has 107,000 OG miles on it and everything else works just fine I'm just lost at this point. Any insight would be extremely helpful, thank you.

 

[Action]

Check engine light on?
Pull codes

Have oxygen sensors been replaced?

What are the parts that have been changed out?

Action

 

[mnmlnomad]

Check engine light on?
Pull codes

Have oxygen sensors been replaced?

What are the parts that have been changed out?

Action

No codes. fuel pump, fuel filter, intake manifold, sparkplugs, radiator, fan clutch, water pump, serpentine belt, pulleys, thermostat, egr valve and solenoid and a few other smaller things have been changed out.

 

[mnmlnomad]

No codes. fuel pump, fuel filter, intake manifold, sparkplugs, radiator, fan clutch, water pump, serpentine belt, pulleys, thermostat, egr valve and solenoid and a few other smaller things have been changed out.

No check engine light either.

______________________________

 

[Action]

I take it the O2 sensors have not been replaced.

No check engine light, the issue is NOT electric engine controls. It is a non-electronic engine issue. (There is an exception to this)

In your list - (fuel pump, fuel filter, intake manifold, sparkplugs, radiator, fan clutch, water pump, serpentine belt, pulleys, thermostat, egr valve and solenoid) there are a lot of things that would NEVER cause the engine to stall. (Water pump, thermostat and belt)

Lacking insight as to vehicle history and why all of those parts were replaced, I am going to assume some were done because of deferred maintenance. However if the fuel pump was replaced for the stalling issue, that was expensive. The fuel pressure could be tested to determine if that was an issue.

When the fuel filter was replaced was any of the old fuel in the filter inspected? Did any debris come out? If debris came out multiple changes may be needed.

The engine may have vacuum leaks. This can be confirmed with a vacuum gauge reading at idle.

Now for the electronic exception. Oxygen sensors (O2)
Oxygen sensors operate when heated up and have a chemical reaction to the exhaust gas. Basically they signal how efficient the engine is burning the air/fuel charge. The PCM uses this signal to adjust air/fuel ratio on each individual injector in more or less real time.
O2 sensors only trip the CEL light if they fail or stop working. However, as they age they get slow. Slow is not good. Because the PCM needs that signal immediately to make the adjustments to fuel injectors. If you are driving at part throttle and have been for some time that mixture is very lean. Accelerate moderate to WOT the fuel mixture needs to go rich to support the power needed. In the first few second that may not happen on old O2 sensors. So too when coming to a stop just a slight amount of enrichment of the fuel mixture is needed.

At 100,000 miles the O2 sensors are not as fast as they once were. I change all 4 on my vehicles every 100,000 miles.

Action

 

[mnmlnomad]

I take it the O2 sensors have not been replaced.

No check engine light, the issue is NOT electric engine controls. It is a non-electronic engine issue. (There is an exception to this)

In your list - (fuel pump, fuel filter, intake manifold, sparkplugs, radiator, fan clutch, water pump, serpentine belt, pulleys, thermostat, egr valve and solenoid) there are a lot of things that would NEVER cause the engine to stall. (Water pump, thermostat and belt)

Lacking insight as to vehicle history and why all of those parts were replaced, I am going to assume some were done because of deferred maintenance. However if the fuel pump was replaced for the stalling issue, that was expensive. The fuel pressure could be tested to determine if that was an issue.

When the fuel filter was replaced was any of the old fuel in the filter inspected? Did any debris come out? If debris came out multiple changes may be needed.

The engine may have vacuum leaks. This can be confirmed with a vacuum gauge reading at idle.

Now for the electronic exception. Oxygen sensors (O2)
Oxygen sensors operate when heated up and have a chemical reaction to the exhaust gas. Basically they signal how efficient the engine is burning the air/fuel charge. The PCM uses this signal to adjust air/fuel ratio on each individual injector in more or less real time.
O2 sensors only trip the CEL light if they fail or stop working. However, as they age they get slow. Slow is not good. Because the PCM needs that signal immediately to make the adjustments to fuel injectors. If you are driving at part throttle and have been for some time that mixture is very lean. Accelerate moderate to WOT the fuel mixture needs to go rich to support the power needed. In the first few second that may not happen on old O2 sensors. So too when coming to a stop just a slight amount of enrichment of the fuel mixture is needed.

At 100,000 miles the O2 sensors are not as fast as they once were. I change all 4 on my vehicles every 100,000 miles.

Action

I'll have to take a look at my last receipt from the mechanics, I believe they did mention something about the o2 sensors being changed but I may be wrong. Thank you.

 

[wa9zug]

I'll have to take a look at my last receipt from the mechanics, I believe they did mention something about the o2 sensors being changed but I may be wrong. Thank you.

Have you replaced the relays in the little black box near the brake booster? FP, WOT, and EEC.

 

[Action]

Why would one replace an electrical relay, for an engine stall when coming to a stop?
A relay is an on off electric switch.
A relay either works or does not.

Action

______________________________

 

[oktowncar]

Using non-OEM parts ( ie. fuel pump, etc, ) may add gremlins on top of the issues

 

[Norms1stTC]

Clean the MAF

 

[wa9zug]

Why would one replace an electrical relay, for an engine stall when coming to a stop?
A relay is an on off electric switch.
A relay either works or does not.

Action

What happens is if there is a slightly intermittant relay contact and/or the socket it plugs into, it will act as an on/off switch. It is a common occurrence in this vintage townie. Happened to me on my last 95,

 

[Action]

OK, if it is a common occurance, I would suggest swapping relays. And the problem will show up somewhere else IF that moved relay is an issue. Based on these forums, I have not seen bad relays are a common ocurance for engine stall. Would be interested in seeing other threads about that.

Replacing them is throwing parts at the problem with no diagnosis or confirmation that a given relay is the problem.

And based on what the OP is stating, the OP is not doing the work. A tech is doing the work.

Action

______________________________

 

[PEPE' LINCOLN]

I'll have to take a look at my last receipt from the mechanics, I believe they did mention something about the o2 sensors being changed but I may be wrong. Thank you.

I had and have a borrowed 96 TC had a leaking manifold go around with a carb cleaner with snorkel and spray lightly in areas of the intake if RPM changes you found your leak. another thing was a mass air flow sensor. no one here can diagnose a car without having it. but I can tell you you're Simpton sound like mine and my fix was what I mentioned, intake. since your post I'm hoping you solved the issue. but if not, also check brake booster. when you stop it robs the vacuum from the system and if you have a leak, it likely could stall but the booster could also be robing vacuum in on itself . ask yourself when you hit the brake does the brakes feel different? when it stalls does it feel different? boosters can fail without noticing it's a booster problem till later on. don't forget the vacuum "pot" and the vapor collector for the fumes of the gas tank and check the gas cap. it's another problem at times. these things generally show up on the check engine light. there are technical names for these things but I'm a body man, so under the hood are cars i own or buy to resell. I know a lot but not everything. fixing wrecks, you are always finding things that has happened in the system from the wreck, so you try to fix yourself seldom we send a car out. too much money! ;}

 

[PEPE' LINCOLN]

No codes. fuel pump, fuel filter, intake manifold, sparkplugs, radiator, fan clutch, water pump, serpentine belt, pulleys, thermostat, egr valve and solenoid and a few other smaller things have been changed out.

intake manifold is Trickey, my friend had a 97 for black car service and when all done 3 were replaced, install is a difficult chore and plastic intakes can be an issue. I changed mine and it was bad and got it from NAPA. and he didn't want to give me mechanic cost.