1998 Nissan Frontier King Cab 4WD 2.4

Starts and runs..all is good...then intermittently I will lose power during acceleration and even while traveling at a steady speed. This happens to the point where I will have to pull over. The motor will idle just fine but when I step on the throttle the motor will oscillate in a steady rythmic order that only varies when I vary the throttle. If I shut her down and turn the ignition off and wait thirty seconds and then re-start all is good again for maybe 300 feet or sometime 100 miles then it happens again. It doesn't usually happen on the highway, usually on the back roads while doing about 20-30mph. I changed the fuel filter without improvement and I am waiting for a fuel pressure tested to come from a catalog order, but it seems like it is electrical as it is so rythmic.
Any ideas?

Love my Nissan...

 

Sounds like the fuel sensor in your throttle body is bad, I dont believe they are that expensive to replace. That would be the first thing I would repalace along with the fuel filter then I would look at the 02 sensor, heck you might want to check that the 02 sensor still has the wire plugged into it. The 02 sensor can be found on your exhaust in the motor compartment.

 

I picked up a OBD2 scanner and found that I got a code 325 Knock Sensor. I guess my check engine light bulb is out.
Now I'm not sure if the sensor is causing the problem or if it is just doing it's job and sensing that the engine ain't quite right.
I pressure washed the engine in an attempt to move any wires that are out of position or to show any "shiny spots" on the harness, but so far the same problem exist. When it runs, it runs well. Then out of the blue it will just cut out. Shut off the key and roll for a while, start it back up and all is good. Sometime for a quarter mile and sometimes for 100 miles.

I did put a meter on what I believe was a connector to the Knock Sensor and it read open to ground. I tried to short it out to the negative terminal on the battery, cleared the 325 code but the code came back after about five minutes of idling. I also tried leaving the sensor unplugged but it still showed up on the scanner.

 

NismoGismo,

I can't find a fuel sensor in the Haynes manual. Did you mean the fuel temperature sensor? Isn't this the one that people bypass with a resistor for a HP boost?

Sleddog

 

I think I got it! Seems like the coolant temp sensor was either dirty or erratic of just low enough off coolant to set it off, (although nothing showed on the OBD2). I added some Slick 50 coolant system cleaner, topped off the system and so far it's been OK!

 

New here...
I had kind of the same problem, so I took it to my local Midas ($64.95 rip off), and they ran a "system scan". Turns out it's the same exact scan that Advanced Auto Parts (formally Western Auto) runs for free...and both showed the same thing. It read that I had a misfire on cylinder #3. I replaced the cap, rotor, plugs, wires, and PCV valve...oh yea...and the air filter also. It seemed to fix the problem. My rotor had a small burned spot on it. The truck was "shuttering" and "shaking" going down the road, and I couldn't get it over about 40mph. It felt like the truck was going to come apart. Incidently...I can't get to the #6 spark plug...so if anyone has any ideas on this....please help. I've tried just about every combination of wobbles and extensions that I have in the tool box...but no luck.