jumpy acceleration, strange activity

[fbcbeer]

1999.5 Pathfinder, 130k miles

-Last night, I pulled up to a stop light, and the car died. Wouldnt re-start.
-Pushed it into a gas station, filled it to the top, still wouldnt start.
-Towed to a mechanic.

-The mechanic said it was a bad distributor harness. I told them to replace it. I picked it up and it ran, but had jumpy/jerky acceleration from a stop right up to 2k rpms. This issue was not there before the car died.
-If you give it more gas, it accelerates fine and doesnt jump.
-If I keep my foot steady lightly pressed on the accelerator, occasionally the rpms will shoot up, but the car doesnt go faster, then it kinda jerks and keeps going.

-I took the car back, they said it was probably the plugs and wires since they were the original parts. Had them replaced and the jerking issue is still there.

-6 months ago, replaced the distributor and cap
-1 month ago, replaced air filter and fuel filter


Anyone have any ideas on where to go next? I dont want to spend more money getting things replaced that arent the issue.

[fbcbeer]

Also, occasionally the check engine light comes on for a knock sensor.

[1999 DesertRunner]

Absolutley no recent problems...and putting a lot of miles on it. But, about a week ago, with about 160k miles, it started bucking, the tachometer would jump up and down...lost power, it would recoup and run ok, but a block or two later, the same..the tachometer bucks up and down..it seems like it was getting gas alright. I went over to a buddy and looked things over...found the air intake-elbow was cracked from heat/age and sucking air in. Found the part and waited a few days to get it delivered. Replaced it, cleaned out the soot...it ran fine for about 30 minutes and took it on the interstate and again, started bucking.. I hobbled home down side streets.

Its not throwing out any codes.

Could it be the cat converter, or the distributer, or something as simple as a dirty fuel filter?


About a week after posting, I took it out again, and it was worse, sounded 'contsipated', and still bucking. I took out the cats....it ran okay, up to around 35mph, but started a backfire and again bucking..tjhere was a sound like bb's rolling around in the muffler, but just pieces of the cat guts

So, did/had the following done: fuel filter, and it ran a code for the knock sensor. Changed that out, and also since I was at about 160k and never knew if the timing belt was changed, had that taken care of, along with the water pump, other belts, radiator flush, etc...the timiing belt was original, and then found out, it never had a tune-up, with plugs wires etc...while the distributer was out, with the intention of just putting on a new cap..found the shaft was binding and small shavings came out...a bad bearing or something else, but not a good sign..so, changed that..

Its running great now.

I couldnt isolate what the cause was...maybe it could have been just putting in a new distributer...and could have saved the cost of the knock sensor, etc...but, it was long overdue for a tuneup, and of course, the timing belt!
I had a past problem...called it bucking.

I had that fixed and a tune-up and it runs fine again.