'98 Pathfinder kind of lurches

Maintenance/Repairs
1

(It has 220K miles) This started suddenly the day after a painless 450-mile trip – It will run fine for a few minutes, then starts jumping like it’s running out of gas (but it’s not). Then the lurching stops and it runs fine. Repeat . . .etc. New fuel pump 2 years ago; yesterday mechanic changed spark plugs, distributor, crank position sensor . . . but still doing it. Help!

2

You need to give a better description of the conditions under which this happens. At idle? (How does it idle?) At X speed? Only above/below X speed? Only while accelerating? Only while cruising? Comes and goes if…?

Automatic or manual transmission?

When the mechanic did all of this stuff was the fuel pressure checked?

3

Thanks for helpful questions (I’ve never done this)! Sometimes idle is a very little rough, but usually fine. Seems to kick in around 2000 rpms, but not consistently. Can be absolutely fine at all speeds (and I think it’s been fixed), or can do it in all gears but 1t (5-speed manual). I will ask about fuel pressure . . . Thanks again,

4

When was the fuel filter replaced last???

5

Thanks for the thought – he did that yesterday with the spark plugs and the other stuff :frowning:

6

Is there a check engine light involved? If so, what are the exact error codes? (format: “P1234”)

If the plugs/wires/distributor (cap only?)/fuel filter were just replaced and it is still running poorly then here is what I would be doing:

  • check fuel pressure under load
  • clean MAF sensor, if equipped
  • check air intake snorkel for hidden splits/cracks etc.
  • put a vacuum gauge on it to check for exhaust clogs / funky valve behavior
  • check air and coolant temp sensors
  • check compression
  • look at oxygen sensor outputs/fuel mix.

Its all busy work that would mostly cost labor time. I’m not a mechanic and I could do all of that in hour. (Compression should have already been done when the plugs were out.

7

Thanks so much – I passed those on to the mechanic. He said that the error code was for the crank position sensor, which he replaced. . . I appreciate your jumping in with all the ideas! (whole distributor replaced). The weird thing to me is that sometimes it runs perfectly. A frustrating few days!

8

There isn’t an error code that tells you that the crank sensor is bad. There are plenty of error codes that refer to the crank position sensor - usually to its circuit. I surely hope he didn’t replace the crank sensor for want of a simple wiring fix. A bad/loose connection could easily give you intermittent issues like this, and replacing the sensor won’t necessarily address that - because the sensor itself might be fine.

Here are the basic crank sensor circuit codes:
P0335 Crankshaft Position Sensor A Circuit Malfunction
P0336 Crankshaft Position Sensor A Circuit Range/Performance
P0337 Crankshaft Position Sensor A Circuit Low Input
P0338 Crankshaft Position Sensor A Circuit High Input
P0339 Crankshaft Position Sensor A Circuit Intermittent

There are others that involve the crank sensor circuit (e.g. out of synch with cam). He should spend some more time with the wiring for the CkPS

9

It was 0335 – so he’s now checking the wiring. You just might be a genius. :slight_smile:

10

Now he’s trying throttle position sensor . . .