The one about the misfire, again!

I've scanned through this forum in the hope of seeing similar faults and fixes, however my little C3 has a mind of it's own.

Picked it up for very little money, a clean 3 previous owners 1.4 SX...but with a misfire.

I am fortunate to have Diagbox/Lexia so I immediately diagnosed the No.4 injector issue, so readily referred to. I replaced the injector with a new one and the misfire was still present. However there were no faults, initially. I took her for a very painful short run and returned quickly as the misfire and lack of power was unbearable. This time it referred to multiple cylinder misfires as a fault.
So I replaced the coil pack and spark plugs. I found it had been fitted with NGK plugs previously.
The misfire / rough idle was still there. Although, with a slow right foot she would pick up revs without too much fuss. With a snap acceleration, she would miss a beat and then continue to rev.
So I started to think about engine timing and valve clearances. The valve clearances were fine. I know the timing is out because I could have sworn I felt the belt slip when I was rotating the engine.
That is next on my list.
And that's as far as I've gotten.

I've purchased a head gasket kit and will remove the cylinder head if I have to!! Although, I'm hoping that just changing the intake manifold O rings will help. This is my second car and as such its' repair can be done at my leisure. However, it is my backup car! So I really need to get it sorted. lol

I suppose what I'm after is a definitive list of 'actual' faults and the corresponding repairs for this misfire issue.

1 or more injectors replaced?
Injectors harness?
Coil pack and plugs replaced?
Engine wiring loom?
Throttle body replaced?
Accelerator pedal replaced?
Accelerator pedal wiring fix?
Leaking manifold gaskets?
Other air/vacuum leak?
Timing issues?
Fuel pressure/flow issues?
Lambda sensor?
Other ECU sensor?
The ECU?
Wiring loom or wiring plugs?

Car doesn't run at all, at the moment, so no chance for any live data.

Thanks.

gjb02storm wrote:I know the timing is out because I could have sworn I felt the belt slip when I was rotating the engine.

gjb02storm wrote:Car doesn't run at all, at the moment,

Hi gjb02storm

I am not at all surprised the car won't run at all if the timing belt has the possibility to slip. This can happen when the teeth shear off the cam belt. I would check the cam belt before doing any more on any other part.