How do you check for vacuum leaks in a 1999 jeep grand Cherokee limited. your problems are irregular idle no heat but air conditioner works and cruise engages but continues to increase in speed.?

Answer 1

Sounds like three separate problems.visit http://www.heatertreater.net/ for the heat problem, unless you want to spend over $1000 to fix the heat problem only.

It sounds dumb, but the best way to check is to run the cruise control. The cruise control system is also vacuum actuated and failure of the CC is almost a definitive diagnosis of a vacuum leak.

If you suspect a leak, the first thing to is make a visual check under the hood for loose lines. It is common for hoses to slip off or "rot". To trace a leak, you will need a vacuum pump/gauge. Harbor Freight has a cheap one or you can usually get one from one of the major parts chains under their "lend a tool" program. Check with us at heatertreater.com if you need additional help.

cgallen