Check spark plug for damage / deterioration. Also check sparking gap & adjust if necessary. Clean the plug & thoroughly & remove any sooty deposits from its terminals. Check High Tension lead/s for damage & HT boots for solid connection. Check rotor arm and terminals in distributor cap for wear / damage. Make sure no water is present in distributor assembly. (Spraying with GT80 / WD40 or similar usually cures this problem). Check fuel hoses for any pinches or holes, replace if required. Check the compression in that cylinder using a vacuum guage, and the functioning of the inlet & exhaust valves. Also check the condition of the valve-stem seals (a common problem) and replace as a matter of course. In more extreme cases of wear, a valve may need to be "re-seated". This requires specialist machine tools & tooling. If it is necessary it is best to do all the valves in one go. Check & clean carburettor or fuel injection system. This is not reccomended for the inexperienced. There are many small components inside these parts that are easy to loose or break. You will also require a new set of gaskets for rebuilding. Consult a workshop manual for specific details & diagrams on your make & model. Cars with engine management systems are best refered to trained mechanics. Disconnecting such systems can sometimes reset them... this could mean spending a fortune having the thing properly recalibrated. Check condition of the cylinder, piston and rings. This is a big job and definitely requires experience. Refer to a workshop manual and multiply the number of parts you need to replace by the number of cylinders in the engine! As a general rule of thumb, dont dismantle anything complicated if you are inexperienced and cannot afford for the vehicle to be off the road for an extended period! Learn on vehicles that dont matter!
check your coil make it is firing both cylinders alternate plug wires to see if opposite cyl is firing if so is a safe bet that coil is the problem
To check if cylinders are firing, you can use an ignition timing light or a cylinder compression tester. With an ignition timing light, you can observe the flash of the light at the spark plug wire to see if it is firing. A compression tester will measure the pressure in each cylinder; if a cylinder has low or no compression, it may not be firing properly. Additionally, you can visually inspect spark plugs for wear or fouling and listen for engine vibrations or misfires while running.
I can't tell from here. Check the spark plug in the #5 cylinder, and the ignition wire to the plug.
need cylinder order for 351 wins
check your compression on #4 cyl
It is probably an ignition problem. Check the mis-firing cylinder's ignition cable from the distributor to the spark plug. A quick check would be to replace the ignition cable on the mis-firing cylinder with one from a firing cylinder. That can rule out the cable. You could have also have a broken or fouled plug. or a bad distributor cap. Carbon tracks inside or on the outside of the cap can allow the spark to jump to ground. If it isn't that, then you have a collapsed lifter or something more expensive.
The firing order for a Renault Megane, particularly for its common inline four-cylinder engines, is typically 1-3-4-2. This means that the first cylinder fires, followed by the third, fourth, and then the second cylinder. However, it's always advisable to check the specific engine model and year for any variations in firing order.
You should check the battery,transmission, and maybe the engine
Run a compression check and see if you have a dead cylinder. you should check you timing Check the firing order.
Firing order is 1-2-3-4-5-6. You migth be able to check cylinder numbers by looking at the distributor markings.
Run a compression check on all cylinders. If that cylinder has low compression you have a burned valve or bad head gasket.
Firing Order: 1-8-4-3-6-5-7-2 check the top of the intake manifold (the thing the carb is bolted to) usually in front of the carb. The firing order should be stamped into the intake. You need to know where number 1 cylinder is on the distributer. count clockwise.