Thread: Revs Dropping on brakes

Not sure if LR are the same as Jeep in having a Vacuum compensator switch which raises the revs on vac drop.

My ZG Grand Cherokee used to do exactly what you have described and thats what it turned out to be but Ive never come across it on any other make.

The problem with my switch was it was cracked and when it would open to do what ever it did it was letting in air which then dropped the revs to nearly stalling but then compensated it by upping the revs electronically which not only made it very interesting to drive in traffic but very thirsty.

Originally Posted by mcrover

Not sure if LR are the same as Jeep in having a Vacuum compensator switch which raises the revs on vac drop.

My ZG Grand Cherokee used to do exactly what you have described and thats what it turned out to be but Ive never come across it on any other make.

The problem with my switch was it was cracked and when it would open to do what ever it did it was letting in air which then dropped the revs to nearly stalling but then compensated it by upping the revs electronically which not only made it very interesting to drive in traffic but very thirsty.

Check out the Valve on the back of the plenum chamber, it controls the air at or near idle, first check if the bolts holding it are tight, I've seen a few that are loose, remove and clean carbon off, also check the wiring plug to the AFM/MAF, pull it out and clean it with contact cleaner spray and refit, make sure it is stable, not loose, Regards Frank.