Hey guys. I just picked up another XJ for the wife during the winter months. It is an 89' with 184,000 miles on it. I test drove it and it had no problems (down a small gravel road), it is not leaking anything and all the fluids were good.

After driving it for awhile, two problems showed up.
1.) When stopping (like at a red light) it lurches forward.. like the engine revs and it tries to go forward. This continues untill you give it gas to go again.
and
2.) When slowing down from 55+, it shakes pretty bad when you let off the throttle. it stops and smooths out at about 50.

It shifts really smooth (better than my 99 in fact) and the engines runs good (aside from the lurching at stoplights). Any ideas? I dont know all that much about all the vacume lines and stuff on the earlier xjs... I only paid 900$ for it so i dont mind putting some cash in it to get it running right.

Thanks!

 

The vacuum system on the older cherokees are a nightmare! But that's where I'd start as far as the "lurching" goes.

As for the vibration on decel, I'd start with checking the u-joints in the driveshafts (both front and rear since the front turns while driving, even in 2wd).

 

Thanks man... i dont even know where to start with the vacuum system haha... I guess ill do some more reading and see where to start. Was hoping it would be some kind of sensor. Much easier for me to do.

 

The tiny vacuum lines like to get hard and brittle and break easy. Some places sell complete replacement vacuum junction blocks (mounted on the front top of the intake manifold) with the lines.

Try running the engine and listening for a vacuum leak (like a "sucking air" sound).

 

You wouldnt happen to have a link to such a place would you?

 

Or if I find a cracked/missing/broken hose.. can I use any heat resitant air line or does it have to be the exact size etc.? Thanks man

 

I got mine from the local Chrysler/Jeep/Dodge dealer, but here's what you want:

http://www.carparts.com/details/Jeep...FVFgMgodujcAcg

This one is for the rear position. You'll want to look at getting the front position one as well.

 

Honestly, anything that won't cause a leak works. For some of the connects on my jeep I had to use electrical tape wrapped around the ends of the lines to fit snugly into the worn factory connectors. Everything works good for me

 

Thank you man. I apreciate the help.

 

No problem! I hope that fixes the problem, or at least helps you out!

 

Renix Vacuum Harnesses
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting, and is called the front harness, is Napa part number BK 715-1367
　

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151367_0269070623
　
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.


http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151366_0269070622

　

The tube from the rear of the valve cover to the intake manifold is part number 715-1365.


http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151365_0066877355

　

Revised 09-11-2012