Why does my Jeep idle like a vacuum?
One thing a fellow Jeeper told me this morning while looking for this source of the rougher idle is he posed the question to the cams on the HO motor. He asked if they were more aggressive which would cause the slight shake. Seems like a good question. You mentioned in your origional post that “it sounds like a vacuum leak”.
What does idle bogging under load mean on a VAC?
What it sounds like to me is you have a vacuum leak. Idle bogging under load is a pretty common sign of a vac leak. Easy way to test for a vac leak without any gauges is to spray break parts cleaner or carb cleaner all over the motor while its running and when your idle jumps thats the area where your vac leak is at.
What causes rough idle on Jeep Grand Cherokee?
Spark Plug Wires – While not every model and engine combination of vehicles today comes with spark plug wires (a lot are now coil on plug), if your Grand Cherokee happens to have them, they can go bad and cause a rough idle. Here’s a great video on how to diagnose bad plug wires with a multimeter.
Can a vacuum leak cause a rough idle?
So far so good with my ride, but the HO motor could cause issues ay beyond a vacuum leak giving you rough idle. Yeah that was me that suggested that rear evap hose over the axle, but these hoses are separated from the intake by the purge solenoid.
Why does my Jeep make a vacuum leak noise?
The vacuum leak noise you complain of can be decently common with air passing through the IAC, the plastic intakes dont insulate the noise as well as metal intakes. You may want to remove your throttle body, unscrew the IAC from the throttle body and clean both the throttle body and the IAC well with some throttle body cleaner.
Why is my Jeep running at a high idle speed?
There are multiple reasons that an engine could be running at a high idle speed but in Jeeps this can often be linked to vacuum leak issues, idle air control (IAC) issues, or throttle malfunctions. If your check gauges light comes on, you should also make sure these items are addressed and that any light mechanisms are in good condition.
What it sounds like to me is you have a vacuum leak. Idle bogging under load is a pretty common sign of a vac leak. Easy way to test for a vac leak without any gauges is to spray break parts cleaner or carb cleaner all over the motor while its running and when your idle jumps thats the area where your vac leak is at.
So far so good with my ride, but the HO motor could cause issues ay beyond a vacuum leak giving you rough idle. Yeah that was me that suggested that rear evap hose over the axle, but these hoses are separated from the intake by the purge solenoid.