Hi all,

I just bought a 95 grand Cherokee Laredo. Its solid through and through except for a vibration at Idle (only when In gear). It sounds Like a transmission problem but, it never slips, ever. It shifts better than any car Ive had. I thought it may have been a tranny mount bought I guess not it seems in OK condition. There's no play in the drive shaft either. Are these cars OBD1? The RPM's range from 5-800 when at Idle IN gear.

Im comming from and explorer (94) and a 95 mustang. So teach me the ways of Chrysler!

Also we Have changed oil and sparks.

PS: I did use the search button and found an Identical post to mine just no real responses.

Thanks for any help.

 

just throwin ideas at you but check your cat.....it might be rattling...i know mine is

 

I know the muffler is loose, or something along the exhaust is. If you push on it while its running it makes half of the noise go away. But that could cause the the Rough Idle only in gear? How do I "check it"?

I will also clean IAC tomorrow after work.

Thank you for helping

 

Mine has a vibration at idle with the A/C on. I just deal with it.
There was a Chrysler TSB out for a vibration at 2100 RPMs while driving in overdrive. There was a revised trans mount and bracket available to fix it. But this most likely is not your problem.

 

No, OD is smooth. Just when you put it in any gear it goes to hell and vibrates, enough to move the rear view mirror. Sounds like when Someone has there sound system up high in the car and it rattles the windows.

Now it dips to 3-400rpms in gear and acts like it wants to die but doesn't.

 

When it dips down does it sound like it has a big cam? Then it shoots back up for a sec then back down ect...If so it sounds a lot like my wifes car did when the fuel pump was going south.

 

Yeah it goes up and down erratically. I reset the battery yesterday and now when in gear it sits even lower.


Is there anyway to test the pump?

 

Other than listening not that I know of. I am sure there are plenty of ways to check voltages or gas output but I dont know any.

 

First I looked for a fuel pressure gauge and it turns out you have to do a order for it.. -Replaced the motor mounts (for me the passenger side was the worst) in the jeep, cap + rotor, wires, plugs, and fuel filter, clean the IAC and throttle body (very dirty). next is the cat (rattles) and possibly fuel pump. Its great its just it still vibes a little and I attribute that to a bad cat. Its MUCH MUCH better after mounts replaced... wow. took about 6 hours though, smh.

 

I would attempt to clean throttle body, and iac good. Unhook battery for a while to reset comp. Re hook and then start and idle in drive for 5 to 10 min. shut off and restart, see if that works. Best thing is its almost free.

 

already done and it improved a lot, just need to fix that cat and possibly the fuel pump.

 

the easiest way to check cat is to get under there and give it a few good wacks and see if you ear and rattles.....you prolly will and if its all jacked up your o2 sensors can cause a ruff idle from telling the computer the wrong fuel mixture to pump through the injectors

 

Ok I just replaced the cat and we tried it out today, idles great at full stop, but feels like the motor surges when you let it idle coast. We get it home and start taking off the plugs start it and so forth (unpluging #1 made no difference to the engine; plug was good, had spark), well we get to plug 4 and my bro pre-starts it before I tell him to and i drop the plug, there was no spark. The only voltage we get is to the distributor but not out to the plugs. I did my research and people seem to go for the CrankshaftPS first, so I ordered it and got it today and I cant put it in till WED. New 02 sensor as well.

I hope this works, this car has been nothing but a money pit since we bought it..3 days of work.

Also we tried putting the old cap and rotor on, and it didn't work. But while doing that I noticed the Haynes book said the #1 spark plug sits two positions behind the front screw, while the new cap has the tip next to the screw labeled #1. Which is right?

 

I have the same problem also. My cat was gutted out by the previous owner. I also need to change my o2 sensor. Have you found your problem?

 

it turns out we burnt the computer, bought a new one, and replaced the plugs with champions. come to find out it was a loose boot on the spark plug. I cant be sure if it was the ECU failing or what. because we had some strange things come up on the display, ("4x4 sensor failed", etc ours is not 4x4). but a combination of new mounts, ECU, cat, o2, and the right plugs seemed to get it back on track..I just cant believe after changing the wires on that car 3 times i didn't get the #6 plug on right.