Ford zx2 gas cap light engine stalls

need to have it check for trouble codes...most auto parts will do it for free

I have no idea why any parts were installed

You always check for codes & use them to
diagnose the system with the fault

You may need a professional scan tool along on a road
test to look at data as well as get caught up on some
maintenance

It would be really nice to know EXACTLY which code you are getting. However, since you mentioned gas cap, I will assume that you are getting Diagnostic Test Code (DTC) P0457.

First, you need to understand that DTCs (or fault codes) NEVER tell you what parts to replace. They only tell you which of the many circuits and systems monitored by your onboard computer network is malfunctioning. The circuit or system must then be properly diagnosed to determine the actual CAUSE of the failure. To do that, you need to follow the correct diagnostic procedure and you also need to know how the system is supposed to work, so you will know a malfunction when you see it.

Here is what is causing your confusion:
The standard definition for DTC P0457 is "Evaporative Emission System Leak Detected (fuel cap loose/off)"
Please note here that the part about the fuel cap is in parenthesis. The MAIN description is "Evaporative System Leak Detected." This fuel cap part is only because this code is very often caused by people not putting their fuel cap on correctly, forgetting to put their fuel cap on at all or losing it, or refueling their engine with the engine running. So, this part of the DTC description is NOT telling you to replace the gas cap. It is only telling you to check for a loose or missing gas cap for a possible cause because it is so common.
What the code REALLY MEANS is that there is a HUGE leak in your EVAP system.

Please also note that a fuel tank pressure (FTP) sensor that is not working correctly can also cause the computer to "think" that there is a huge leak when there is not...Hence, the need for proper diagnosis.

The operation of the FTP needs to be verified to make sure it is not "lying to the computer. All of the hoses, lines, tubes, charcoal canister, and other components of the EVAP system need to be inspected for cracks, tears, breaks, etc. that would cause a leak in the system.

P0457 FORD - EVAP Control System Leak Detected (Fuel Filler Cap Loose/Off)
EVAP control system has a very large leak such as fuel filler cap fell off, EVAP control system does not operate properly.

Vehicles that meet enhanced evaporative requirements utilize a vacuum-based evaporative system integrity check. The evap system integrity check uses a Fuel Tank Pressure Transducer (FTPT), a Canister Vent Solenoid (CVS) and Fuel Level Input (FLI) along with the Vapor Management Valve (VMV) or Electric Vapor Management Valve (EVMV) to find 0.040" diameter or larger evap system leaks. Federal vehicles can utilize a 0.040" leak check rather than the 0.020" leak check required for California vehicles (click over pic for zoom).



Symptoms:
- Engine Light ON (or Service Engine Soon Warning Light)
- Possible a noticeable fuel odor caused by the release of fuel vapors

Possible causes:
- Missing fuel filler cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap

Possible solution:
- Retight or replaced fuel tank filler cap

Tech notes:
It is a very common problem with Ford vehicles. There are service bulletins for the following vehciles:
1997-2000 Ford CONTOUR
1997-2002 Ford ESCORT
1997-2003 Ford CROWN VICTORIA, MUSTANG, TAURUS
1998-2003 Ford ESCORT ZX2
2000-2003 Ford FOCUS
2002-2003 Ford THUNDERBIRD
1997 F-250 Ford HD
1997-1999 Ford Ford F-250 LD
1997-2003 Ford E SERIES, EXPEDITION, EXPLORER, F-150, RANGER, WINDSTAR
1999-2003 Ford F SUPER DUTY
2000-2003 Ford EXCURSION
2001-2003 Ford ESCAPE, EXPLORER SPORT TRAC, EXPLORER SPORT

Also, in this link could check this Ford Bulletin.

Hope helps (remember to rate and comment this answer).

You need to try and get a code off of your computer for the check engine light. Check and make sure your gas cap lid is on.

It is the fill pipe rubber seal

I doubt the two problems are connected. I would try a new gas cap and see what happens since it runs fine. The service engine soon light won't reset on it's own right away.

Your fuel filter will not set a fault code. If you have a lean mixture code it could be a dirty mass air flow sensor or possible O2 sensor. Each codes will represent a specific component most of the time but the fuel filter will not set a code.

The error that I'm showing for error code P1133 is 
P1133 Heated Oxygen Sensor (HO2S) insufficient switching bank 1 sensor 1(Rear Bank).  I would suggest having both of your Oxygen Sensors replaced if you haven't already had that done.  Hope this helps.  Thanks for an honest rating and for using FixYa.

Your symptoms can be from many things however I have seen this often from stopped up fuel filters in several different cars.
It could also be from very bad gas.
My suggestion is that if the car has high mileage OR you have recently goten gas from an unfamiliar service station, you shoudo change the fuel filter and put some good fuel additive in (after the new filter) to get rid of any water or other contaminates in the gas tank.
I recommend "SeaFoam". It is more expensive that others but has a very good reputation. It really works!

Armin W.