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Out of Focus

My '04 Focus ZTW sometimes hesitates and dies in warm weather, especially after I’ve just filled up with gas. In the winter (we’re talking Iowa here) it starts and runs faithfully, even at 15 below. I’ve had sensors replaced (manifold absolute pressure sensor; mass air flow sensor) as well as spark plugs and wires. No one else I know with a Focus has had this problem. It’s a fine car otherwise. Why does this happen? It’s especially scary in traffic.

Just a guess, but perhaps your Vapor Recovery System (fuel tank vent) is allowing too much tank vapor to be directed into the engine, flooding it…Think “purge valve” “carbon canister”, stuff like that…

I was thinking the same thing as Caddyman based on 2 things - one is the mention of after having gotten gas. The other is warm weather. I wouldn’t be surprised if you had either a bad vent valve that is allowing raw gas into the evap system or perhaps a problem with the purge solenoid and/or its vacuum lines.

Presumably there is no check engine light?

I think you’re on to something. The check engine light usually doesn’t come on when the Focus has its “episodes”. The last mechanic to work on it mentioned tank vapor and said not to “top up” when I get gas, which I’ve stopped doing. Thanks for the suggestions.

Thanks for the suggestion. The last mechanic mentioned tank vapor and said not to “top up” when I get gas. A “purge valve” replacement would no doubt involve disemboweling the car and help reduce the national debt. I never have quick or cheap repairs, it seems:)

Need clarification here: when you say you stopped “topping up” you mean that until recently you were attempting filling the tank, after the initial release/click of the fuel pump ???

Yes. I haven’t done that since last summer, though. Must be something to do with heat-related vapor expansion. If I periodically just open the gas cap, will this help?

I think we’re definitely on to the solution.

Topping off the tank is a terrible, terrible habit to have. It is a sure-fired way to GREATLY increase the risk of damaging the charcoal canister.

If you haven’t had this problem since last summer and you’ve stopped topping off the tank, then just watch and see if it reappears. You might get lucky and it might dry itself out, but that isn’t terribly likely…

If it doesn’t, you’re looking at $205 for parts from RockAuto if you have the 2.3L ($323.89 from Ford). If you’re lucky and have the 2.0L, it’s $105.24 from Ford. Labor would probably run at least an hour on top of that…

Thanks so much! I’ll see a mechanic soon!