What is wrong if my mercedes s 500 1995 v8 is running on 4 cylinders only.I have checked the spark plugs, plugwiers ,two destibutors and routers and thy seam to be allrite .The car has got two coils asswel

The removal of # 3 & # 4 tells you those cylinders are
contributing the most ,as removing the wire causes the motor
to stop
My guess is that the other cyl #1 & #2 are not firing at all, if there
is no change

If you had a V6 or V8 it would continue to run,not so with only
4 cylinder

Learn or study the ignition system & replace any ignition control
module that fires the first two cylinders

Get an HEI Test Spark Plug & put the plug wire to that & ground it
& see if you get spark,check all the plug wires one at a time.

Don't forget timing belts that are worn & slip,battery voltage,alternator output & A/C Ripple coming out of it

I would check compression or better yet, do a cylinder leak down test.
Could be you have worn valves in #1 & #2 thus little spark
Check fuel pressure at motor with a gauge

What about spark plugs and plug wires on those two cylinders with no spark? This is a v8 engine, you didn't mention the other cylinders? The rotor turns when you crank it?

Check wiring harness.. could have a break in it... causing it to stop firing..

Hi Atsy,
I'd believe that the problem could be a bent distributor cam shaft (The center shaft inside the distributor.
Have it checked and if I've been a clever boy you can give me a rating
Regards Johngee10

HI, did you try checking the ignition coils. I had the same problem in my car I replace the one ignition coil where there was no power and that solve the problem. try not to buy cheap ones those will blow fast. you can find the Bosh original ones in the internet for a fare price. today at the dealer are about $212.00 each.

P0300 Random Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
according to this fault codes first mark ignition coils
3 ---------------- 6
2 ---------------- 5
1 ---------------- 4
RB-------------LB
this right banks and left bank, please remove Ignition coils with lids and spark plugs from right bank and swap with left bank, if fault code change as
P 0304 Cylinder 4 Misfire Detected
P 0305 Cylinder 5 Misfire Detected
P 0306 Cylinder 6 Misfire Detected
You can Identify it's a faulty ignition system then next swap ignition lids from ignition coils be careful each coils have two lids one short and other long bit deference and when you remove and fix it to the car keep in mind correct order because each coil two different fire for two spark plugs don't mix up, if you mix it can create the fault code.if you detect any fault ignition coils or spark plugs or lids replace that and also whether god or bad recommend to replace spark plugs, find the right that's most important thing, if this way couldn't found the any ignition fault next step is check fuel presser, when the engine running fuel presser must be around 4.5 bar without engine running must be 4 to 6 bar if the fuel presser too low need to check two different things one is fuel pump other is fuel injectors, in this case you can swap injectors from right bank to left bank and find is the injectors leaking, if not leaking faulty fuel pump.is this information helped you? if yes please leave a comment,

For the 1984 Ford F150:
I do not know if you have the 4.9L In-Line (Straight) 6-Cylinder, the 5.0L V8, or the 5.8L V8; however I have included all below.

For the 4.9L In-Line 6-Cylinder:
Firing Order
1-5-3-6-2-4
Cylinders:
(back)
...6
...5
...4
...3
...2
...1
(front)
Distributor:
...........4
.....2
[].............1
..6.............[]-clip
.............5
.....3
Rotation: Clockwise

For the 5.0L V8:
Firing Order:
1-5-4-2-6-3-7-8
Cylinders:
........(back).......
|...4...|......|...8...|
|...3...|......|...7...|
|...2...|......|...6...|
|...1...|......|...5...|
.......(front)
Distributor:
..[]....5...1
4................8
2................7
....6....3..[]-clip
Rotation: Counter Clockwise

For the 5.8L V8:
Firing Order:
1-3-7-2-6-5-4-8
Cylinders:
........(back)........
|...4...|.......|...8...|
|...3...|.......|...7...|
|...2...|.......|...6...|
|...1...|.......|...5...|
........(front)
Distributor:
..[]..3....1
7..............8
2..............4
....6....5..[]-clip
Rotation: Counter Clockwise.


Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!

SOUNDS LIKE NO FUEL TO 2,3,5,8 CYLINDERS

Hello, What you could have is and ignition problem. I have had to replace many distributor caps (2) and rotor buttons (2) on this model to solve this same problem.
I hope this helps.
CYA, Gtaor241

not coil coil it wouldnt fire at all it is either a plug or a wire replace the wire and plugs and that will fix it