Z31 missing on #4 cylinder

0202 is injector on cylinder 2 , 0302 is misfire on cylinder 2.
Why did you change plugs, coil pack, wires, 02sensor when there is probably no/intermittant signal feeding injector 2.
Check for signal on the injector. If non, work backwards towards the ECU.

well that firing order is wrong!
an Opel Kadett 200ie, 1996
no country told and 15 engines used world wide this car.
last one in UK is 1995
so I guess it is not UK?
sold under 11 names world wide.
IN UK it is really a Vauxhall Astra Mk II. badged as Opel. now that is confusing.
not diesel, but petrol AND ALL ARE INLINE 4 BANGER'S.
every car made ,every manual for for them in print tells you 2 answers ( distributors)
1: lost all distrib setting
2: or not lost SETTINGS, Crank not turned.

so read that book it tells you to do this.

SPIN ENGINE TO SEE DISTRIB ROTOR ROTATION CCW OR CW/? (HOLD THAT THOUGHT)
by hand
set crank pulley TO TDC ,-0 DEGREE'S AND BOTH VALVES CLOSED #1 CYLINDER. (CALLED FIRING)#1
CAP OFF. MARK ROTOR #1 TO DISTRIB BODY
THEN CAP ON AND MARK #1 ON CAP.
PUT #1 WIRE TO #1 CAP
AND 1,3,4,2, IN CW OR CCW DIRECTION SEEn ABOVE. at FIRST STEP.

DONE car runs.
if distributor was pulled there are 15 engine answers.

next time on all cars made on earth with HV spark wires
do them 1 at a time. and win.
distribs or any car with HV spark wires seen (sets)

Sounds like a spark plug or distributor problem.... Change out all your spark plugs and check your wires for breaks. Check fuel injectors for build-up.

If you shoot me your year I might have the info you need. And - depending on your year - the 94ish years had TWO coil packs for the 4 cylinder - 8 plug wires basically. When any of the leads of either of those coil packs goes out - youre going to experience a miss condition. If it's the v6 - you've got a cam sensor that can cause that type of action - and have you checked your throttle positioning sensor? If that goes out - the ecu will get mixed signals and can act like that as well. If you can tell me the year I'll see if I got the info you need. All the best.

If its a DIS ignition system , change the plug wires , they may look OK but that dont mean they is OK.

your crank position sensor does not read individual cylinders, only the position of the crank shaft. make sure the plugs and wires are good, check the spark coming from the coil, make sure there are no vacuum leaks at intake manifold, check timing, then do a leak down test to make sure you don't have a bent or damaged valve in the cylinder head.

The easiest way personally to check for a misfire is (with old set of plug wires though) ground a test light. Poke through each plug boot at distributor. If it makes engine miss more not a problem cylinder. When you get to one where there is no change, that is the cylinder that is missing. Not saying that it will cure your problem, but it would rule out the good cylinders that are operating correctly. Make sure you don't touch bare metal because it will shock you. It might not miss either unless under load. Firing order is 18436572 ccw on cap. 1 cylinder drivers side closest to radiator. Drivers side 1357,passenger side 2468. Looking from front of engine to back of engine.

Hi I have a 1995 C200 Auto Sedan chs WDB 2020202F241703, I think I have a problem in the ECU. Only runs on two cylinders, I have changed the core pack on the 1 & 4 cylinders but the problem persists. The other problem is I don't know where the ECU (engine computer ?) is can anyone help ?

If the plugs, wires, and coil are all good then it can be a partially clogged injector, or low compression on that cylinder. It can also be a bad ECU. My cousin had a 99 Taurus with the exact same problem and it turned out to be the ECU which he had to replace. The ECU is very expensive so make darn sure everything else is good before you replace the ECU. It could be the coil has an intermittent problem and may show good especially when cool. You might try putting that coil on a different plug position, resetting the ECU, and see if you get the same code PO301. Run a compression test on all cylinders to see if you have good compression. Add a can of Seafoam Fuel Treatment to a full tank of fuel to make sure the injectors are clean. Check all wiring closely for frayed wires or loose connections. Eliminate all other possibilities before looking at the ECU itself.

Recheck the firing order; 1-6-5-4-3-2

On the distributor passenger side radiator to fire wall. 2-4-6-coil
On the distributor drivers side radiator to fire wall. 3-1-5

Cylinder passenger side radiator to fire wall. 2-4-6
Cylinder drivers side radiator to fire wall. 1-3-5

Good luck and also check the distributor cap again for proper seating.