Spark plugs have a factory-set gap between the electrodes at 1.1 mm, sometimes when there is a misfire that is difficult to determine, especially at idle speed, it is recommended to reduce the gap to 0.8-0.9 mm. Recently, there have been unfavorable opinions about NGK candles, apparently the reduction in quality took place after the production was transferred from Japan to France, so below is the list of substitutes.
List of substitutes:
Champion REC14PYC, Beru 14FR8MU2, Bosch FGR8MQPE, Denso K16HPRU11, Denso KH16TT, Denso VKH16, Denso IKH16, NGK LFR4AP11, NGK STK 5613, Renault 7700113267, Renault 8200034236
Copper core cables are best, but ferrite core cables can also be used. Good quality ProLine cables can be purchased from Janmor.pl (No.RB31) or very good quality Czech Tesla cables. NGK cables (No. 44248) and the original Renault 820122243 are also available.
Ignition cables should be replaced with every second spark plug replacement, i.e. from 60,000 to 100,000 km
The symptom of cable or coil damage is usually uneven idling and acceleration, while when driving at a constant speed, the engine runs smoothly.
Ignition coil Sagem
Often the problem is also the Sagem ignition coil number 7700873701 8200141149, which causes uneven engine operation. Due to the aging of the plastic housing, cracks often occur in the area of the mounting bolts. It is also damaged internally, which is invisible from the outside, which makes it difficult to diagnose the damage. This is especially true for coils with black leads. The coils with the white ones (in the photo) are of better quality.
The order of the wires in the picture with the first cylinder from the gearbox side.
The problem of high-quality spark also applies to ignition cables that hardly anyone replaces, and as a result of aging processes they lose their properties. The most common damage is the burning of the core inside the cable, so the damage is not visible from the outside, while the spark generated there significantly weakens the spark on the plugs. It should be added that damage to one wire causes problems and a spark in two cylinders
The highest quality platinum or iridium spark plugs are recommended for the F5R engine. The fuel injected into the cylinder at the spark plug may differ slightly from the stoichiometric ratio, which may lead to difficulties with ignition of such a mixture. The service life of platinum plugs is at least 30,000 km.
Iridium spark plugs, also available for the F5R engine, have even better parameters. The lifetime of iridium candles is at least 50 thousand. km.