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Ask William D. Mulneaux Your Own Question
William D. Mulneaux
William D. Mulneaux, Auto Mechanic
Category: Car
Satisfied Customers: 224
Experience:  ASE engine performance, brakes. GM and Chrysler certified
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1998 jeep grand cherokee limited quadra trac 5.2v8-when ...

Customer Question

1998 jeep grand cherokee limited quadra trac 5.2v8-when watching it on my obdII scanner between 1200 and 2000 rpm the timing does not seem to advance. Anyway when driving it stutters or jerks only at this rpm range like it has fuel issues.I have replaced distributor & module,CPS,Air charge sensor,TPS,map,fuel pump,alternator,timing chain,fuel injectors,intake and plenum gaskets,oxygen sensors(both)and transmission(thought maybe lock up chatter).Now if the temp is between 63 and 78 according to overhead display it runs perfect with power to spare. My next step is going through and checking all ecm and sensor grounds. The only code it has ever sent and does not trigger check engine light is 1683-speed control relay.Not sure which one it was so replaced all(in compartment under hood next to radiator resivoir).I give up man not to mention I''m broke now. ANY SUGGESTIONS?
Submitted: 9 years ago.
Category: Car
Expert:  William D. Mulneaux replied 9 years ago.

Welcome to Just Answer,

Do you have a scanner?

Can you get me long and short term fuel trims while it is stuttering?

All of the work you have done I assume you checked all of the u-joints? I have seen u-joints bite people because they only check for looseness. I find it best to pull the driveshaft and make sure the joints aren't sticking.

I would not expect to see much change with the advance unless under an extreme load.

Did you change the flex plate when you changed the tranny, a warped or cracked flex plate will throw of the CKP signal.

Try a couple of things if you have not already:

1.)Power brake it through the RPM range and see if the stutter is there

2.)Try running in first or second gear and stick in that RPM range and see if it will stutter continously.

3.)Pop it in neutral while it is stuttering and see if it goes away.

Make sure it is RPM related and not speed or load related, it sounds like you are not sure because of the parts you have replaced.

Did you switch any parts to the transmission you replaced, was it used or reman?

A possibility it does not sound like you have looked into are the speed sensors, if one of them is bad it could cause some crazy shift or lock up problems.

I know I am asking a lot of questions, but I can't look at the truck myself so I have to rely on yor info. Bear with me and we will come up with something.

Good Luck,


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Customer: replied 9 years ago.
I can either kick down and power through it or manually shift through and no problems. It seems to only do when it goes into the last gear(torque conv. lock up) and especially bad if going up hill.So it seems to be load related. As far as the tranny it was used, but my neighbor is a certified tranny guy and we went through it and replaced the clutches and steels,bands, and bushings also replaced the speed sensor and speedo pick up as well.The flywheel(flexplate)looked fine.The only other thing is at idle it has what feels like an intermittent miss and it pretty much stays there until about 2000 rpm and it smooths out like a sewing machine, no misses.As far as that speed control relay where is it located? When I replaced all the relays did I replace the right one? Do the speed sensors send any kind of code or is something you diagnose with a volt-meter.I do not have a scanner just a code reader that shows O2 sensor and timing advance etc...
Expert:  William D. Mulneaux replied 9 years ago.

I know this might sound strange with all the work you have done, but have you had a compression test done. You are telling me it has a miss at idle, you may have a sticking valve or weak valvespring.

A vacuum guage can tell you a lot about the valve train with out having to pull all of the plugs and doing a compression test. With all the work done and no positive results I would go back over the basics.