The Jeep petrol V6 Engine fitted to both the Cherokee, The Wrangler and the Grand Cherokee. A common fault that arises with this is a generic fault code for “misfire cylinder X”.
It’s not uncommon for mechanics to turn to spark plugs and ignition coils for this fault. Given what’s involved to get to the plugs and coils (the inlet manifold is required to be removed) its also where we would advise as a starting point too.
Its not uncommon for these engines to then either have the misfire fault return or never even go away after the coil and plug replacement.
If you are getting generic Misfire fault codes or “multiple cylinder misfire detected” codes.
If this is the case, the next step and a very common fault is the fuel injectors fail. Jeeps will sometimes log a fault code directly relating to a fuel injector but not always.
If you are getting injector codes or generic misfire fault codes. It is advised to replace the fuel injector. We advise buying this only from Jeep. Electronic components can be sourced cheaper from across the world however when it comes to electronics cheap is never better.
We do advise the replacement of all six injectors whilst doing this repair. Again the labour required to remove the inlet manifold justifies the additional spend.
In Summery if you have misfire fault codes and plugs and ignition coils have not helped. Time to replace the fuel injectors.