# 1991 Jeep Wrangler 4.0

**URL:** <https://community.cartalk.com/t/1991-jeep-wrangler-4-0/69319>\
**Category:** Maintenance/Repairs\
**Created:** [November 8, 2011, 3:19pm UTC](https://community.cartalk.com/t/1991-jeep-wrangler-4-0/69319 "2011-11-08T15:19:06Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![4sasha](https://avatars.discourse-cdn.com/v4/letter/4/47e85d/32.png) [@4sasha](https://community.cartalk.com/u/4sasha)\
**Post date:** [November 8, 2011, 3:19pm UTC](https://community.cartalk.com/t/1991-jeep-wrangler-4-0/69319/1 "2011-11-08T15:19:06Z")

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Vehicle will not exceed 20mph. Vacuum leak can be heard coming from around the intake area on the driverside. Can not detect where it is coming from. All vacuum hoses seem to be connected. I need help

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**Author:** ![chaissos](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/chaissos/32/2347_2.png) [@chaissos](https://community.cartalk.com/u/chaissos)\
**Post date:** [November 8, 2011, 6:31pm UTC](https://community.cartalk.com/t/1991-jeep-wrangler-4-0/69319/2 "2011-11-08T18:31:54Z")

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I use a cigarette, and follow the smoke to find vacuum leaks. You can also use a type of gas that will burn and listen for engine RPM change, but I find a smoke works pretty easily. Helps a bunch if the fan isn’t running, but it’s not necessary. Your first step is to find the leak. Only then can you be advised on repairing it.

That or take it to a mechanic.

Good luck,  
Chase

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**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\
**Post date:** [November 8, 2011, 8:00pm UTC](https://community.cartalk.com/t/1991-jeep-wrangler-4-0/69319/3 "2011-11-08T20:00:57Z")

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Chaissos cigarette idea is a good one, but a stick of incense would be tons cheaper. Unless, of course, you’re a smoker anyway.

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**Author:** ![4sasha](https://avatars.discourse-cdn.com/v4/letter/4/47e85d/32.png) [@4sasha](https://community.cartalk.com/u/4sasha)\
**Post date:** [November 15, 2011, 1:41pm UTC](https://community.cartalk.com/t/1991-jeep-wrangler-4-0/69319/4 "2011-11-15T13:41:46Z")

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smoke can be seen coming from the thottle body where the throttle position sensor mounts. Mount screws are tight.