HELP! ' 96Grand Cherokee i6; shudder & jerk

[jgc96ltd]

HELP!

I have a '96 GC Ltd I6 maintained by the one & only local dealership here in Kuwait.

The GC runs fine for the first 10 minutes, then shudder & jerks while running - as if the motor were going to shut-off or the transmission is having hiccups. When pulled onto the shoulder and put it into neutral the rpm is very erratic flucturating between 700-2200rpm. After restarting, the exact same thing happens.

In the past four days the dealership has changed virtually all the sensors including the PCM and not been able resolve this issue.

All HELP/ADVICE will be appreciated - thanks and have a good one.

[Ron68]

Originally Posted by jgc96ltd

HELP!

I have a '96 GC Ltd I6 maintained by the one & only local dealership here in Kuwait.

The GC runs fine for the first 10 minutes, then shudder & jerks while running - as if the motor were going to shut-off or the transmission is having hiccups. When pulled onto the shoulder and put it into neutral the rpm is very erratic flucturating between 700-2200rpm. After restarting, the exact same thing happens.

In the past four days the dealership has changed virtually all the sensors including the PCM and not been able resolve this issue.

All HELP/ADVICE will be appreciated - thanks and have a good one.

Check the fuel filter and strainers. Seems like fuel starvation.

[jgc96ltd]

Originally Posted by Ron68

Check the fuel filter and strainers. Seems like fuel starvation.

Fuel filter was replaced, wheter the vechicle is idling erratically/smoothly the fuel pressure at the injectors is on par. Where would the strainers you refer to, be located at?

Meanwhile thanks & have a good one.

[Cam7]

The shuddering and Jerking usally is a Fuel problem, bad fuel pressure. When I test for this I connect a fuel pressure guage and check the pressure while driving. Could be a couple of other things like a EGR -stuck, Vacuum leak. The first ten minutes everything is good sounds as a sensor is shorting out when it gets warm. Does the check engine light come on? Check for codes by turning the key on then off then on and count the flashes. the dealership should be able to fix this, it should show up on a Scan. Also check the voltage double check for vacuum leaks.

[Ron68]

Originally Posted by jgc96ltd

Fuel filter was replaced, wheter the vechicle is idling erratically/smoothly the fuel pressure at the injectors is on par. Where would the strainers you refer to, be located at?

Meanwhile thanks & have a good one.

If your 96 is the same as my 97, then the filter is located on the top of the pump/regulator/filter/quantity sender unit in the fuel tank. The unit is basically a metal can (sometimes called a volute). On the bottom of the can is a small plastic mesh bag which is one of the fuel pump strainers. Located inside the can at the bottom is the fuel pump and attached to the pump pickup tube is another strainer. The purpose of the can is to keep the pump and it's pickup immersed in fuel so that the pump doesn't lose it's prime. Attached to the side of the can is a small module and float arm which is your fuel quantity sender unit. Attached to the top of the can is the fuel filter and fuel pressure regulator, which is where your fuel line and return line hooks up. The Jeep stealer will try to sell you one for about $650.
If you had your filter replaced, that still would not fix the problem if the strainers are getting clogged. I had it happen to me on my 97. The strainers were clogged with rust from bad filters on the pumps where I had bought gas. It was a process that took a year or so to happen before there was enough crud built up in the tank to clog the strainers. (I had removed the tank to change the fuel sender module and the tank was clean then) Changing the filter wouldn't have helped as the blockage was upstream from the filter.
I had a rough idle once and I replaced my spark plugs. I still had the rough idle and I replaced the plug wires and that fixed the problem. How old are your wires?

[fourx4forfun]

had one do that, ended up being a hairline crack in the distributor cap.

[jgc96ltd]

Originally Posted by fourx4forfun

had one do that, ended up being a hairline crack in the distributor cap.

Thanks to all for the suggestions/recomendations given. I got the problem fixed.

I HAVE TRADED THE DAMN THING IN - and am processing the paper work on a brand-new Mitsubishi Nativa with full options .

Thanks once again.

[fourx4forfun]

those are pretty sharp, i get to see all the new ones come in as my bldg is located right next to the n american regional headquarters for them, they always have some brand new ones in their parking lot waiting for a dealer, they have some cars and a couple of trucks right now, the trucks look real good. but none of them have the towing capacity of the Grand Cherokee V8.