MY12 WK Grand Cherokee Diesel - miss/flat spot

[IanC]

My Jeep has developed a miss/rough spot at around 1200 to 1500 rpm and the dealer has no idea what's wrong. So far the dealer has tried "updating some driving codes" and doing a carbon clean. While the engine does run much smoother when warm the miss is still there. It is worse when cold and is very noticeable. And by the way, the Electronic Throttle warning light has come on twice over a period of months but the dealer said that was not the problem. Any ideas??

[IXPLOR]

I just had a MAF replaced on mine however mine went into full limp mode

[IanC]

Hi, Forgive my ignorance -- "MAF"??

[Barboots]

Mass Air Flow sensor. [emoji106]

[GCDingo]

It is attached to the air intake tube just after the airbox. Kittle thing with a wire connector sticking out. Maybe buy a can of MAF sensor cleaner and pull it out and spray. Can be bought from any auto parts store. It's only 2 screws to get it out. Just don't drop it as it is fragile.

[Classic Boy]

Originally Posted by IanC

My Jeep has developed a miss/rough spot at around 1200 to 1500 rpm and the dealer has no idea what's wrong. So far the dealer has tried "updating some driving codes" and doing a carbon clean. While the engine does run much smoother when warm the miss is still there. It is worse when cold and is very noticeable. And by the way, the Electronic Throttle warning light has come on twice over a period of months but the dealer said that was not the problem. Any ideas??

If after checking all the usually 'suspects' sensors etc,
ask for a compression check, as many modern CRDI engines coke up their inlet valves and this can lead to rough running and misfire because the coke prevents one or more inlet valves closing properly. It can occur as early as 50-60K kms on some makes.

I tell CRD owners to "drive it like they stole it" at least once a week or so to help remove the coke buildup.

[IanC]

Hi, Thank you to both responses - will try both suggestions and let you know how it goes.