Hi! This has been a long-term issue with my 2006 1.6 cmax petrol. Every now and then, the car doesn't start immediately. I can hear the engine turning over, but it's as if no fuel is getting through. It always happens after I’ve been driving and then try to start it again about an hour or two later. So it must have something to do with the engine temperature. I have to press the accelerator slightly, and then it starts right away. It never feels like it’s flooding (like old carbureted vehicles used to), but rather the opposite: a lack of fuel, because I never smell any fuel afterwards.

A few times, the idle has been very unstable for about 5 seconds, around 500 to 700 rpm. In those cases, giving a hard press on the accelerator can stall the engine, but if I press the accelerator slowly and gently, it seems to stabilize the idle. Once it revs up past 1000 rpm, it returns to normal. Apart from that, the idle is always stable and the car always starts on the first try and never stalls, regardless of the outside temperature, whether the engine is cold or hot. The Ford scan shows no errors, except for a chronic one related to the battery charging circuit. Do you have any idea what could be causing this?

Excessive carbon build up due to age and not being revved enough probably

Run some decarb through it or cataclean and run it on super unleaded

Then give it a real good blast getting and holding the revs over 4,500RPM for a bit each time

 

30 minutes ago, DaveT70 said:

Excessive carbon build up due to age and not being revved enough probably

Run some decarb through it or cataclean and run it on super unleaded

Then give it a real good blast getting and holding the revs over 4,500RPM for a bit each time

 

Thanks! Do you think that the carbon it's on the injectors? So time ago I was used a injector cleaner, but no luck

It would be valves and pistons

Thanks, really!

...about 6 months ago, I took the car to a mechanic… a totally unprofessional one, to change the crankshaft pulley. He messed up the timing and ended up replacing the engine with another one (according to him, with fewer kilometers, but who knows!).

The thing is: it's doing exactly the same thing now as it did before. Very occasionally, but exactly the same symptoms.
That's why I was asking if you thought it could be the injectors, because all the components around the block are still the same (sensors, injectors, etc.), but the block itself is another.

It would be valves and injectors then, but probably still pistons too.

Try as recommended and see if it helps

2 hours ago, DaveT70 said:

It would be valves and injectors then, but probably still pistons too.

Try as recommended and see if it helps

Thanks! I will try it