2003 - Won't start when warm - sometimes

Hi all. I have a 2003 Taurus - Push-rod motor. 116k miles. Well maintained. Had a professional tune-up done just before 100k....plugs, wires, fuel filter.

So here is my deal...sometimes after a long or medium trip, when I turn off the car, and try to start it up in just a couple of minutes....it will start, but run like crap for about 100 yards...then die. Then it will not start at all for about 10 or 15 minutes. If I just sit there for awhile, let it cool down some, then it will start and run like a top until the same thing happens a few weeks later.

This doesn't always happen - only on occaision. Happened maybe 4 times in the last 6 months. It has always been after trips of 30+ miles...until the last time. The last time it happened - just a couple of days ago - I only went to grocery store....run in for two minutes...came out and it happened. As soon as I start it...it chugged like crazy...died after 100 yards....and would not start. It cranks like crazy....just won't fire. Let it sit for 15 minutes....then it starts...and runs perfect.

Battery and alternator are new - so juice is good. I think spark is good....so I'm thinking fuel? My filter should be ok...so I'm fearing the worst....fuel pump? If it was fuel pump...would it even run at all? I had one go out on an old grand prix I had...and when it went - it went quick.

Any suggestions?

Sounds pretty consistent with a weak fuel pump. The pump is an electric motor and once it gets warm it can start to fail just like how you describe. It would be good to confirm that you don't have fuel pressure but do have voltage from the inertia switch to confirm the problem is most likely the pump.

-Rod

No, I don't think it's the fuel pump. Cause if it's the fuel pump, it dies in one shot, it doesn't jerk.
Check the 3 ignition coil's resistance. Even if your coil is new, it can be defective.

No, I don't think it's the fuel pump. Cause if it's the fuel pump, it dies in one shot, it doesn't jerk.

In the early stages of pump failure the pump can struggle to provide sufficient fuel pressure. Low fuel pressure = stumble/lack of power.

For a coil to be the problem it would need to be more than one coil to cause it to stall, and it's not too likely that two or more coils decided to fail at the same time. If the trigger for the coil failed though, that would be a different story (ie: Crankshaft Position Sensor).

-Rod

For a coil to be the problem it would need to be more than one coil to cause it to stall

That's false. One time, I disconnected one plug's wire of my Windstar to see what it does. I was obligated to accelerate to start the engine. If I put my foot off the gas, it stalled.

Yes, it can also be the CPS. Good thought.

Sounds like your IAC was not working if a single cylinder misfire caused a stall, or maybe the engine was due for a tune up as well. Certainly there will be exceptions to experiences, but I've never witnessed an otherwise healthy V6 engine that was incapacitated by a single cylinder misfire.

-Rod

Yes you're right, I get an engine damage when it happens. It was the pistons rods.

But auxbar was able to run 100 yards before it stalled. It runs crap, so I think the coil is also possible.

I also want to add that if you disconnect 1 wire, you disable 2 cylinders. Cause each coil is connected to 2 plugs in serial. No ground on the plug, just on the engine. It's not like the old car.

I'll concede that it's too early to rule anything out at this point. Auxbar really needs to determine what the engine doesn't have when it acts up, correct fuel pressure, spark, compression, or air. The first two are obviously easiest to determine. Once it's determined what is missing and preventing the engine from starting it will be much easier to narrow the focus. My first suspect, and probably the easiest to check, is fuel pressure. My preference would be to check it with a fuel pressure gauge. If you don't have one and/or don't want to purchase one, then use a can of throttle body cleaner and meter some in to the intake air path through a vacuum port on the throttle body while someone else cranks the engine over. If the engine starts while the cleaner is metered in, the problem is insufficient fuel. If metering cleaner in to the intake doesn't help, or if you don't happen to have a can handy next time this happens, hold the throttle all the way to the floor and try to start the engine. In the off chance the issue is too much fuel pressure, holding the throttle wide open (WOT) will put the PCM in "Clear Flood" mode and turn off the fuel injectors.

If the pressure is good, then move to spark. An inline spark tester at the coil will be easier than checking at each of the spark plugs. If none of the coils have spark, then check for a trigger from the CKP sensor.

-Rod