I have a 2000 ZTS ford focus, and when it gets hot it starts cutting out and running really rough. it acts like its not getting enough fuel. but it only does it when its hot. I changed the thermostat, the fuel filter, the serpentine belt, changed the oil and the coolent. I took it to the shop and they dont know what it is. Could it be the fuel injectors? Please help!
have you changed the air filter too? that is not on your list. why?
My guess is that you need to start looking at the ignition system. Because it contains components that can become heat sensitive when they become hot it’s usually the culprit in these cases.
I’m not sure what’s under your hood, a coil or coil pack, but i’d start there. The windings of coils are insulated with a varnish like coating that can crack when it gets old from the repeated thermal expansion and contraction of the underlying wires, allowing the coil windings to short out as the wire expands and the cracks open up.
If you can spray Starting Fluid into the engine intake tube, when it’s running rough, and the engine smooths, that would indicate a fuel problem.
It may be ignition. Click on this link for a picture of the ignition coil: http://www.autozone.com/R,APP697597/vehicleId,1618801/initialAction,partProductDetail/store,1140/partType,00540/shopping/partProductDetail.htm If you had the repair manual, you could test the ignition coil. Play a hair dryer over the ignition coil. If the ohms readings change when the coil gets hot, you’ve found your culprit.