jerking and sputtering at 2000 RPM - clues?

[tigerwoo]

yesterday I was driving down the freeway and all of a sudden my pathfinder started acting as if I was going to run out of gas. I immediately pulled into a gas station and filled up the tank, but still had a good two gallons left at the time of the jerking and sputtering so that wasn't the problem. Upon leaving the gas station I still had the same problem.

The problem occurs whenever I reach ~2000 RPM in any gear. At that point the car begins to hesistate and jerk. I can't reach anything much higher than 3000 rpm. (although not sure as the tactometer bounces wildly) The only way I can drive the car smoothly is if I shift to the next gear before 2000 RPM. I replaced the fuel filter but that didn't seem to help.

Any ideas?

I have a '93 Pathfinder w/180K miles.

[tigerwoo]

As a follow up, Here's some additional info on my problem...

I notice that when the car is cold I don't have the problem. But as the car warms up after a few miles of driving, the RPMs at which I am able to run the car successful (without hesitation and jerking) decreases until it reaches about 2000 which then becomes the threshold. It's like the engine is choking and the muffler also seems to be coughing a bit.

I do have the typical exhaust manifold problem but never had the repair done as I was told it would not affect my pathfinder's performance enough to be worth it. I'm not sure if this now is a contributor of this latest problem.

Someone suggested I replace the fuel filter and spark plugs which I did, but didn't solve the problem, so I'm still seeking a solution if there is anyone that may know.

I will probably have it professional checked out.

[Joe Nicklay]

Originally Posted by tigerwoo

As a follow up, Here's some additional info on my problem...

I notice that when the car is cold I don't have the problem. But as the car warms up after a few miles of driving, the RPMs at which I am able to run the car successful (without hesitation and jerking) decreases until it reaches about 2000 which then becomes the threshold. It's like the engine is choking and the muffler also seems to be coughing a bit.

I do have the typical exhaust manifold problem but never had the repair done as I was told it would not affect my pathfinder's performance enough to be worth it. I'm not sure if this now is a contributor of this latest problem.

Someone suggested I replace the fuel filter and spark plugs which I did, but didn't solve the problem, so I'm still seeking a solution if there is anyone that may know.

I will probably have it professional checked out.

I am having the same problem with my 91. I had a clogged catalydic converter and replaced it and that did the trick for a few weeks. It started again and I disconnected the vacume line to the ERG valve and plugged it with a bolt. Now it only does it when the engine is cold. The next step is checking the injectors and replacing the manifold exhaust gaskets. Try injector cleaner first. Maybe you will have better luck them me.

[rebeitler]

This sounds like a problem i encountered in the mid 90's with a 90 Pathy that had 275,000 on it at the time. I'll try to keep this story short. I replacd everything you can think of, including the CAT conv., timing sensor on the distributor, the distributor, tune up parts, and lastly, a new set of injectors. None of these things were the problem although sometimes the vehicle would run better for a short while immediatley following the replacement.

Finally my cousin, who is a Benz mechanic, tried something that surprised me greatly for it worked. He took the bundle of wires that run from the throttle body in his hand hand pulled them straight out with a decent amount of force. He did this while the vehicle was trying to idle. For a few short seconds the idle smoothed out the vehicle sounded great again. The rough idle and stalling, etc. returned but he had found the problem, or shall we say, he found the general location of the problem. After 4 days of testing the entire lengths of each of these wires we found two wires that lead directly to the injectors were damaged INSIDE the wiring insulation. They had been damaged by heat over time. When signifigantly cold they performed OK, but once warmed up they expanded with the heat of the motor and could only conduct voltage intermittently. This caused the bucking, low RPM, rough idle, etc. Fuel was only reaching the injectors intermittently.

If this is the same problem you should notice that it has gotten worse with time, repacing parts temporarily "fixes" the problem, and what started out as an inabilty to cruise with no load on the engine has progressed to a very rough running engine, especially when warm.