High rev after lifter swap

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Jul 22, 2015 | 08:00 AM

Mdjeep

Thread Starter

Newbie

Joined: Jul 2015

Posts: 9

Likes: 0

Model: Cherokee

High rev after lifter swap

I just replaced lifters in 2002 grand cherokee 4.0. I put everything back together and when I start it it want to rev to the max. I retorqued intake, checked all electric connections and vacuum hose. Any ideas on what would do this?

Jul 22, 2015 | 09:04 AM

Fred/N0AZZ

CF Veteran

Joined: Jul 2013

Posts: 7,554

Likes: 17

From: Monett, MO.

Year: 1999

Model: Cherokee

Engine: 4.0

Welcome to the forum!

This needs to be posted in the Grand Cherokee section for the best response.

Jul 22, 2015 | 09:38 AM

XJPat

Seasoned Member

Joined: Jan 2011

Posts: 437

Likes: 0

From: Central Jersey

Year: 91

Model: Cherokee

Engine: 4.0 I6 H.O.

Re check the vacuum hoses.

Jul 22, 2015 | 11:16 AM

Mdjeep

Thread Starter

Newbie

Joined: Jul 2015

Posts: 9

Likes: 0

Model: Cherokee

Ive checked all vacuum hoses. When I unplug map sensor. It does not rev high just runs bad. I can control throttle with peddle it just misses bad. This is not making sense at all.

Jul 22, 2015 | 11:28 AM

DFlintstone

CF Veteran

Joined: Aug 2011

Posts: 10,489

Likes: 24

From: Nor-Cal Coast

Year: 90,84

Model: Cherokee

Engine: 4.0,2.5

You likely have a big vacuum leak somewhere, or something is holding the throttle open. Did you pull the injectors? Those lower O rings can leak vacuum. Use water from a dish soap bottle to check?
Also, I'm not sure how fast it would go with the IAC stuck open.......